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Fischer-Tropsch synthesis (FTS) offers a promising route for producing sustainable jet fuels from syngas. However, optimizing the catalyst design and operating conditions to maximize the desired C8-C16 jet fuel range is a challenging task. This study introduces the application of a machine learning (ML) framework to guide the design of Co/Fe-supported FTS catalysts and operating conditions for enhanced fuel selectivity. A comprehensive dataset was constructed with 21 input features spanning catalyst structure, preparation method, activation procedure, and FTS operating parameters. The random forest ML algorithm was evaluated for predicting CO conversion and C8-C16 selectivity using this dataset. Feature engineering identified the most significant descriptors influencing performance. A principal component analysis reduced the dataset dimensionality prior to ML modelling. The random forest algorithm achieved high prediction accuracy for the conversion of CO (R² = 0.92) and C8-C16 selectivity (R² = 0.90). In addition to confirming the known effects of operating conditions, key roles of Co/Fe-supported properties were elucidated. This ML framework provides a powerful tool for the rational design of FTS catalysts and operating windows to maximize jet fuel productivity. [ABSTRACT FROM AUTHOR]

The necessity for high operational temperatures presents a considerable obstacle to the commercial viability of solid oxide fuel cells (SOFCs). The introduction of active co-dopant ions to polycrystalline solid structures can directly impact the physiochemical and electrical properties of the resulting composites including crystallite size, lattice parameters, ionic and electronic conductivity, sinterability, and mechanical strength. This study proposes cobalt–iron-substituted gadolinium-doped ceria (CoxFe1-xGDC) as an innovative, nickel-free anode composite for developing ceramic fuel cells. A new co-precipitation technique using ammonium tartrate as the precipitant in a multi-cationic solution with Co2+, Gd3+, Fe3+, and Ce3+ ions was utilized. The physicochemical and morphological characteristics of the synthesized samples were systematically analysed using a comprehensive set of techniques, including DSC/TGA for a thermal analysis, XRD for a crystallographic analysis, SEM/EDX for a morphological and elemental analysis, FT-IR for a chemical bonding analysis, and Raman spectroscopy for a vibrational analysis. The morphological analysis, SEM, showed the formation of nanoparticles (≤15 nm), which corresponded well with the crystal size determined by the XRD analysis, which was within the range of ≤10 nm. The fabrication of single SOFC bilayers occurred within an electrolyte-supported structure, with the use of the GDC as the electrolyte layer and the CoO–Fe2O3/GDC composite as the anode. SEM imaging and the EIS analysis were utilized to examine the fabricated symmetrical cells. [ABSTRACT FROM AUTHOR]

In this study, an experimental investigation of a gasoline compression ignition (GCI) engine on combustion and emission fuelled gasoline—ethanol blend (E20). A diesel engine was modified and driven by an electrical motor to control the engine speed at 1500 rpm and IMEP at 4.5 bar. The aim of the given study was investigated to optimize the double-injection strategy including the injection timing of the second injection timing (SOI2), and the dilution ratio as the exhaust gas recirculation (EGR). The SOI2 was varied from −9 to −3 CA ATDC and dilution was simulated by using N2 addition with a maximum level on 25%. It was shown that the combustion phase can be directly controlled by both SOI2 and dilution. For the SOI2 at −9 CAD ATDC, the combustion starts just after the beginning of the second injection and is delayed as a function of the dilution rate. Otherwise, the exhaust gas recirculation level was investigated to study the combustion and emissions characteristic with three cases of second injection timing while the first injection timing, fuel proportion and the intake pressure were kept constant: −35 CAD ATDC, 30%/70%, and 1 bar, respectively. The results have shown that NOx level decreased as a function of dilution for all SOI2 with the smallest NOx level at—3CAD ATDC. However, CO and HC emission increased while increasing the dilution ratio. It is clear for SOI2 is set at −3 CAD but between −6 and −9 CAD, the level of CO and HC emissions is really in the same order of magnitude. [ABSTRACT FROM AUTHOR]

In this study, the adsorption behavior of Cu2+, Pb2+ and Cd2+ from synthetic metal solutions using natural zeolites was studied in order to investigate the efficiency of adsorbents of heavy metals from industrial wastewater. The kinetic study indicated the suitability of the zeolite for the removal of Cu2+, Pb2+ and Cd2+ ions from synthetic wastewater; batch experiments were used to identify the effect of parameters that affect the rate of adsorption such as the adsorbent mass, the initial solution concentration, the initial solution pH, the adsorbent particle size, and the agitation speed and evaluated their impact on the removal efficiency of heavy metals from industrial wastewater using the natural zeolite. Zeolite samples with masses between 1 g and 10 g were contacted with constant volume (100 ml) of multicomponent synthetic solutions containing Cu2+, Pb2+ and Cd2+ ions. They were agitated at agitation speeds in the range of 100–300 rpm for agitation times from 1 hr to 8 hrs in a magnetic stirrer at room temperature, the pH values were monitored and adjusted regularly. Every hour, 15 ml of the samples was analyzed using the Atomic Absorption Spectroscopy. The results show that the removal efficiency of Cu2+ increase from 60% for 1 gr to 99% for 10 gr of the mass of absorbent, increase from 62% for 1% to 94% for 7 of the initial solution pH, increase from 90% for 100 rpm to 94% for 300 rpm of the agitation speed, the amount adsorbed increase from 0.5 mg/g for 100 mg/l to 2.1% for 400 mg/l of the initial solution concentration. Similar results are obtained for the two other heavy metals (Pb2+, Cd2+) and showed that the capacity of the adsorbents for the removal of heavy metals is directly proportional to the mass of absorbent, initial solution pH, agitation speed, and initial solution concentration. The highest adsorption rate of Cu2+, Pb2+ and Cd2+ ions took place in the first hours followed by a slower adsorption rate later on. [ABSTRACT FROM AUTHOR]

Data from literature and a stoichiometric material balance model were employed to estimate associated emissions with flaring of sweet gas in Nigerian oil and gas companies. Emission factors were obtained using AP 42 formula. Results showed that thousands of tonnes, ranging from 6500 to 22,000 tonnes of natural gas were flared from 1997 to 2016. At flaring stack efficiencies of 97% and 98%, the associated emissions are: CH4, C2H6, C3H8, iC4H10, nC4H10, iC5H12, nC5H12, C6H14, C7H16, C8H18, C9H20, CO2, and N2 from unburnt natural gas and in addition to CO2, CO, N2, NO, NO2, H2O and H2 from incomplete combustion. At both flaring stack efficiencies, the amount of emissions from unburnt condition ranged from1,608 tonnes N2 to 9,146 tonnes CO2 all higher than any emission standards in the world, while the amounts of emissions from incomplete combustion ranged from 467,964 tonnes for CO2 the lowest to 2,476,011 tonnes for N2 the highest all higher than any emission standards in the globe. Emission factors of emissions from unburnt natural gas ranged from 0.000090 tonne/tonne for C10H22 to 0.026235 tonne/tonne for CH4 while those of the emissions from incomplete combustion ranged from 0.10285 tonne/tonne for H2 to 1.13137 for CO2 tonne/tonne. It was observed that thousands of tonnes of emissions are released into the atmosphere during flaring of sweet natural gas either at complete or incomplete combustion. It is recommended that flaring of natural gas should be reduced to a minimal level to safeguard the environment. [ABSTRACT FROM AUTHOR]

Solvent toxicity is of major concern in the extraction of lipid from algae biomass via the solvent extraction technique. This study was carried out to determine the optimal solvent mixture (chloroform, methanol, ethanol, and dichloromethane) composition with less toxicity for the extraction of lipids from Scenedesmus obliquus microalgae. Optimization of the solvent mixture composition was performed using augmented simplex centroid design and the influence of cell disruption on lipid yield was assessed. The eco-toxicity of the solvent mixtures was assessed using thermodynamic prediction model. The optimal lipid yield of 19.4% lipid g-1 DCW (dry cell weight) was obtained using solvent mixture composition (1:5:1:1 v/v) chloroform/methanol/ethanol/dichloromethane. The cost estimation and environmental risk parameter values obtained from the use of proposed quaternary solvent mixture composition indicated that lower cost and less toxicity were achieved when compared with the commonly used chloroform-methanol mixture composition. Microwave-assisted lipid extraction gave 55.67% higher lipid recovery from microalgae and the quality of the extracted lipid was unaffected when compared with the conventional solvent extraction. The fatty acid profile revealed the extracted lipids as an appropriate feedstock for biodiesel production. Applicability of lipid extracted biomass obtained using the proposed technique is confirmed by SEM and FTIR analyses. [ABSTRACT FROM AUTHOR]

Nowadays, people are demanding on the naturally derived cosmetic products, including lip balms. However, there is a lack of studies for the physicochemical properties of the formulated lip balms. Besides, there are little publications found on the use of beetroot as an active ingredient and colourant in lip balm formulation. Thus, this study aims to formulate lip balm using beetroot; and test the physicochemical properties of formulated lip balms to get three best formulations. The stability of these best lip balms was conducted for 4 weeks in room temperature and chiller conditions. Finally, a sensory evaluation was conducted to identify consumer acceptance towards the best lip balms. Lip balms placed in room temperature were all stable while few changes occurred for the lip balms placed in a chiller. All panellist preferred the same lip balm in the sensory test. The result of this study can be extended to assess the potential of beetroot in the formulation of other cosmetic products. [ABSTRACT FROM AUTHOR]

Wastewater from oil refinery industries has major pollution potentials with mutagenic and toxic compounds. Due to water scarcity in South Africa, oil refinery industries are compelled to find appropriate technology to treat their wastewater for reuse. With regards to this, most of the chemo-physical treatment processes are inadequate and are faced with major environmental and economic challenges. Therefore, this study aimed to find replaceable and cost-effective coagulants to the conventional coagulant for the treatment of a local South Africa oil refinery wastewater using dissolved air flotation (DAF) Jar tests. Three polymeric coagulants for the removal of turbidity, total suspended solids, chemical oxygen demand, and soap oil and grease (SOG) were investigated. At defined experimental conditions of recycle ratio (10%), air saturator pressure (350 kPa) and pH at 5, each coagulant was evaluated from a dosage of 10 mg/L to 50 mg/L. Above 80% of the aforementioned oily pollutants were removed at the coagulant dosage of 50 mg/L. Among the coagulants evaluated, PASS was found as the most suitable alternative coagulant to alum, to enhance and aggregate the air bubble–oil droplet interface for easy separation by the DAF. From the results, PASS is foreseen as promising and economical for pre-treatment of industrial wastewater, which is due to its lower cost and easy degradability. [ABSTRACT FROM AUTHOR]

This project is primarily aimed at determining the effect of phase inversion on oil-water dispersion from a three-phase mixture comprising of an oil-water emulsion at different oil percentages and air at varying liquid and gas flowrates through a horizontal pipe. Parameters affected by phase inversion were investigated such as liquid-side pressure drop, viscosity and flow regimes. The liquid-side pressure drop was estimated and predicted from existing as well as developed correlations. The results obtained were tabulated and represented graphically. Viscosity measurements were taken at different oil percentages. At inversion, the mixture's continuous phase switched from water to oil as indicated by the increase in viscosity and pressure drop. A significant change in pressure drop was noted for all correlations used beyond the point of phase inversion. The viscosity of the liquid phase was tried to be related with oil percentage empirically to get a Reynolds's no of laminar or turbulence. However, that did not influence the prediction significantly. It was also found that tghe occurrence of phase inversion affected the flow regimes of the mixture causing a shift from a plug dominant flow to a more slug-type flow pattern. [ABSTRACT FROM AUTHOR]

In this study, we aimed to energetically and exergetically evaluate the usage of a hybrid solar dryer system for cassava drying via a series of drying experiments. The experiments were performed beginning at 10.00 A.M. (hereafter, in local time) until the moisture content of cassava starch became constant at a value less than 14% on a wet basis at drying temperatures of 40 °C to 60 °C and drying times of 180–240 min. The results demonstrated that the highest overall dryer energetic efficiency was 20.82%, which was achieved at a drying temperature at 60 °C, and that the maximum energetic efficiency of 27% was recorded at 11.00 A.M. The exergy flows fluctuated during the drying process and were dependent on the solar radiation and drying conditions; however, the exergetic efficiency of the dryer was 25.1%–73.8%. Comparison of the fitting models denoted that the Page model was the most suitable model for describing the experimental drying performances. The calculated effective diffusivity constant (Deff) and the activation energy (Ea) during the drying process from 50 °C to 60 °C were 3·× 10−10 m2/s and 15.3 kJ/mole, respectively. [ABSTRACT FROM AUTHOR]

High-surface area carbon with porous structure can provide a large electrical-double layer as energy storage in supercapacitors. Herein, porous graphene-like materials with high-surface area were prepared from renewable coconut shell charcoal via KOH activation followed by oxidation in a harsh environment using a modified-Hummer method. Using the method, the surface area of the treated coconut shell charcoal increased significantly from about 189.97 m2/g to 642.45 m2/g with a pore diameter of approximately 5 nm. As expected, the increase in surface area increased the capacitance significantly, by up to 46-fold, from 3.22 to 148.20 F/g. These results demonstrated that the low cost renewable porous graphene-like material prepared from coconut shell charcoals is promising for use as electrode material for supercapacitor. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the potential of cashew nutshell activated with H2SO4 as adsorbent for the removal of Cr and Mn (II) ions from wastewater. In this study, cashew nutshell (CNS) adsorbent was prepared using shells of cashew nut (Anacardium occidentale) by chemical activation. Cashew nutshells were crushed for size reduction and the resulting crushed shells were immersed in 1.0 mol L−1 H2SO4 at a rate of 1:10 (m/v) with a constant stirring at 60°C for 4 h. Proximate analysis was carried out according to standard analytical methods and determination of pH, bulk density, and iodine number was conducted. The morphology and functional groups present were investigated by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FT-IR) spectroscopy. The surface area, pore volume, and pore size distribution were also characterized by N2 adsorption at 77 K using BET. Continuous adsorption study in a fixed-bed column was carried out by using CNS as an adsorbent for the removal of chromium and manganese ions from electroplating wastewater. The effect of flow rate, influent concentration, and bed depth were investigated on the adsorption characteristics of the CNS adsorbent. Three dynamic model Clark, Yoon-Nelson, and Adams-Bohart were applied using the experimental data to predict the breakthrough curves using linear regression to determine the characteristic parameters of the column that are useful for process design. Significant values in the moisture, ash content, volatile matter, iodine number, and zero-point of charge were obtained on the adsorbent and compared to literature. SEM images revealed irregular pore structure before adsorption and pores of the CNS adsorbent were filled with chromium and manganese ions after adsorption. The FT-IR adsorption bands observed in the CNS sample confirmed the presence of hydroxyl (-OH), carbonyl, and carboxylic (-COOH) groups involved in sorption of chromium and manganese ions onto surface of CNS adsorbent. The result showed highest BET specific surface area of the adsorbent sample obtained as 608.2 m2/g, pore volume and diameter of 0.2209 cm3/g and 2.116 nm, respectively. The column parameters calculated showed the effectiveness of the column at a flow rate of 5.0 ml/min, bed height of 10 cm and concentration of 20.3 mg/l Mn ion and 21.05 mg/l Cr ion. The percentage removal of Cr ions was 56.40% at an adsorption capacity of 10.79 mg/g and the percentage removal of Mn (II) ions was 53.09%, at an adsorption capacity of 9.82 mg/g. The Yoon-Nelson and Clark models were found suitable for the description of the breakthrough curve. Results reveal that quality cashew nutshell (CNS) adsorbent can be produced from Cashew nutshell thereby serving as an alternative to commercial adsorbent for heavy metal removal from wastewater. [ABSTRACT FROM AUTHOR]

The current oil spill remediation strategies are costly and may be toxic to aquatic species and clean-up workers. There is, therefore, the need to look for alternative oil spill remediation strategies that are less costly and non-toxic. This paper presents the potential of TiO2 and its modified form (Fe-TiO2) to remediate crude oil fractions under the irradiation of sunlight (UV-Vis), visible (Vis) and ultra-violet (UV) lights. The TiO2 and Fe-TiO2 were synthesized by mild hydrothermal method and characterized with X-ray diffraction (XRD), Ultra-violet-visible spectroscopy (UV-Vis), Diffusion reflectance spectroscopy (DRS), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDX). The DRS result of Fe-TiO2 showed an enhanced absorption in the visible light region. The estimated optical band gaps were ~3.12 and ~2.9 eV for TiO2 and Fe-TiO2, respectively. The potential application of TiO2 and Fe-TiO2 in oil spill remediation was investigated through photocatalytic degradation of benzene soluble fraction, n-hexane soluble fraction and 1:1 volume by volume methanol/benzene soluble fraction in crude oil. The degraded crude oil fractions were characterized with UV-vis, Fourier Transform Infrared (FTIR) Spectroscopy and Gas Chromatography-Mass Spectrometer (GC-MS). The FTIR and UV-vis results showed that the Fe-TiO2 was more effective in photodegrading the crude oil fractions under sunlight light irradiation than TiO2. The GC-MS results showed excellent photodegradation of the various crude oil fractions with the formation of new intermediate products. The results from the study show the potential application of TiO2 and Fe-TiO2 in crude oil spills remediation. [ABSTRACT FROM AUTHOR]

An analysis of the literature shows the capability of Computational Fluid Dynamics to represent the hydrodynamics and heat transfer within spray dryers, as well as the prediction of droplet collision, agglomeration and wall deposition. The literature also reveals that no model published so far describes the drying of individual droplets, the study of which is restricted to experimental methods such as ultrasonic levitation. This article presents an Euler-Lagrange three-phase numerical set-up to simulate the drying of individual droplets within a spray dryer. The defining parameters of both phases, i.e. air and the biphasic (solid-liquid) droplets are taken from a barbotine slurry used for ceramic tile production. A single droplet size has been used--the characteristic Rosin-Rammler droplet size from the distribution generated by an actual spray injector published previously in the literature. The model predicts the theoretical linear evolution of the square diameter according to the D²-law, and the temperature and mass exchange with the environment. This unique numerical set-up allows calculating the Stokes number associated with a given trajectory path as well, providing designers with an accurate degree of control over the fate of individual droplets. The proposed model is therefore a powerful tool intended to support the design and optimization of industrial spray dryers. [ABSTRACT FROM AUTHOR]

The geothermal power plant is converting steam to electricity. The evaporation process in the evaporator produces wet steam (brine). The Brine has a high temperature and contains water, which is quite dominating. Therefore, a separator is needed to separate between ammonia-rich vapor that will flow into the turbine and ammonia-poor liquid, which will flow to the regenerator. In this case, the optimal separation uses a vertical separator. The design of vertical separator produces the specifications for brine mass flow rates 55.275 kg/s at circumferential stress 614.93 bar and brine mass flow rates 1.124 kg/s at longitudinal stresses of 1229.87 bar. The analysis result of brine mass flow rate on the lowest circumferential stress was 16.583 kg/s at 573.71 bar, and the highest was 181.372 kg/s at 628.94 bar, while the brine mass flow rate on the lowest longitudinal stress was 1.048 kg/s at 1,147.42 bar and the highest is 1.149 kg/s at 1,257.88 bar. [ABSTRACT FROM AUTHOR]

The acceptance of liquefied petroleum gas (LPG) cookstove has increased across the country in recent years; however, their performance has not been investigated and established. To achieve this, laboratory tests were carried out to evaluate the thermal efficiency, and industrial combustion analyser (E-instrument E8500) was then used to characterize and quantify the air emissions from combustion of conventional LPG cookstoves in the country. The average thermal efficiency for all tested burners was 66.267 ± 7.218% meeting Tier 4 of the International Organization for Standardization, International Workshop Agreement 11. The mean concentration of CO, NOx, HC, and SO2 was in the range of 3–530, 48–810.5, 99–4176, and 0–4,respectively,and the range of CO2 was 1,792–3,592 mg/m3,which were compared with stationary source limit by Federal Ministry of Environment Standard, Nigeria. The toxicity potential of NOx and SO2 was below unity, 25% of the burners tested were below unity for CO, and HC was higher than unity for all tested burners. Most cookstoves met the guidelines for CO, NOx, and SO2. Hence, LPG in Nigeria could serve as a source of energy for cooking. [ABSTRACT FROM AUTHOR]

A solar collector that collects solar radiation from the sun is equipped with a heat absorber kit that can store heat for a long term. This system consists of collector box, acrylic-coated cover, black-coated-aluminum base, and finned absorber. The purpose of using the fin is to enlarge the surface area exposed to the sun's heat so that radiation heat transfer increases. This design is conducted for 460 W collector capacity, 1 m2 surface area, expected output temperature between 60°C and 77°C. Flat-plate solar collector is used for heating the solar-energy-absorber plat. Furthermore, air is passed through the collector to become hot and flowed into the process room by using a fan. Tests are carried out four times, then the results for the lowest and highest output air temperature are 59°C and 77°C and the lowest and highest collector efficiency are 62% and 76%. [ABSTRACT FROM AUTHOR]

A renewable clean energy is sine qua non for mitigation of toxic and greenhouse gas emissions, preservation of natural ecosystem, biodiversity and its sustainability. Hence, this research work focuses on the evaluation of biofuel potential characteristics of Salicornia plant's oil (halophytes) that grows in arid and salt water environment devoid of suitable edaphic and ecological factors that could support the growth and development of normal vegetable plants. Two species of the Salicornia plants were investigated. These are Salicornia bigelovii and Salicornia brachiata. A supercritical fluid extraction (SFE) process using carbon dioxide (CO2) modified with ethanol as extraction solvent yielded 32.14% of S. bigelovii oil and an oil yield of 26.58% S. brachiata. The fatty acid compositional analysis was determined by Agilent, HP6890 gas chromatograph with flame ionization detector (GC-FID). A 30% concentration of Candida antarctica lipase catalyst that was immobilized on a macro-porous, acrylic resin particles was used for the transesterification process. While biodiesel yield of 92.80% and 81.30% were obtained with t-butanol solvent, a yield of 59.34% and 48.76% was obtained in solvent-free system for S. bigelovii and S. brachiata, respectively. Finally, S. bigelovii biodiesel exhibited better cold flow properties but with very poor fuel critical characteristics, such as low cetane number, high iodine value and low heating value, which when applied in diesel engine could result in abnormal combustion, performance and emission behaviour. Whereas, S. brachiata showed a superlatively promising biodiesel fuel characteristics that is typical of those recommended by American and European biodiesel standards, and thus a technically viable diesel alternative in compression-ignition engines. [ABSTRACT FROM AUTHOR]