In this study, we report the first total hemisynthesis of trans-himachalol sesquiterpene, a stereoisomer of the natural cis-himachalol isolated from Cedrus atlantica essential oils, from himachalenes ...mixture in five steps. Reactions conditions were optimized and structures of the obtained compounds were confirmed by IR, mass spectra, 1H, and 13C NMR. The synthesized compounds were investigated for potential activities on various isolated smooth muscles and against different neurotransmitters using molecular docking. The results show that the synthesized compounds display high affinities towards the active site of the protein 7B2W and the compounds exhibit promising activities on various isolated smooth muscles and against different neurotransmitters.
In this study, tin dioxide nanoparticles (SnO
NPs) were successfully synthesized through an eco-friendly method using basil leaves extract. The fabricated SnO
NPs demonstrated significant adsorption ...capabilities for phenol (PHE), p-nitrophenol (P-NP), and p-methoxyphenol (P-MP) from water matrices. Optimal conditions for maximum removal efficiency was determined for each phenolic compound, with PHE showing a remarkable 95% removal at a 3 ppm, 0.20 g of SnO
NPs, pH 8, and 30 min of agitation at 35 °C. Molecular docking studies unveiled a potential anticancer mechanism, indicating the ability of SnO
NPs to interact with the epidermal growth factor receptor tyrosine kinase domain and inhibit its activity. The adsorption processes followed pseudo-second order kinetics and Temkin isotherm model, revealing spontaneous, exothermic, and chemisorption-controlled mechanisms. This eco-friendly approach utilizing plant extracts was considered as a valuable tool for nano-sorbent production. The SnO
NPs not only exhibit promise in water treatment and also demonstrate potential applications in cancer therapy. Characterization techniques including scanning electron microscopy, UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy (XRD), and energy-dispersive X-ray spectroscopy (EDAX) provided comprehensive insights into the results.
In this work, we have studied, formulated, prepared, and characterized the rheological and electrical behavior of a composite material based on an epoxy resin Diglycidyl Ether of Bisphenol A (DGEBA) ...reinforced with hexaglycidyl cyclotriphosphazene (HGCP). The epoxy system was cured with 4,4'-methylene dianiline (MDA). DGEBA-HGCP-MDA epoxy composite materials with reinforced HGCP which varied from 5% to 10% by weight were prepared by mixing in the molten state. The morphology was evaluated by SEM. The rheological behavior was studied using small deformation rheology. The electrical characterization was carried out with a frequency variation range from 1 Hz to 100 KHz at room temperature. These measurements revealed that the rheological and electrical behaviors strongly depend on the quantity of HGCP in the DGEBA matrix. The linear viscoelastic properties study reveals that the modulus of elasticity G' is dependent on the amount of HGCP present in the epoxy resin DGEBA. The capacitance-frequency measurements suggest a distribution of localized states in the band gap of the blends.
Hydroxyapatite (HAp) synthesized through a wet chemical procedure was used to adsorb lead (II) from an aqueous solution. HAp was characterized using Fourier transform infrared, X-ray diffraction, ...Brunauer–Emmett–Teller analysis, and scanning electron microscopy. The removal of Pb
+2
was investigated using the factorial design approach to investigate the efficiency of different Pb
+2
concentrations, adsorption contact time, and HAp mass. The greatest Pb
+2
removal (98.94%) was obtained at a starting concentration of 50 mg/L, a contact period of 15 min, and a pH of 8. At 323 K, the isothermal adoption module was fitted to the Langmuir isotherms with a regression coefficient (
R
2
) of 0.96. The thermodynamic calculations revealed that the adsorption process was exothermic, spontaneous, and predominantly dominated by chemisorption. Furthermore, the maximum adsorption capacity (
Q
max
) at equilibrium was 90.18 mg/g, and the adsorption kinetics was specified by a pseudo-second-order kinetic model. Density functional theory and theoretical studies showed that the results of the experiment were correlated by the observation of a much higher negative E
ads
value for the lead ion adsorbate molecules as they attached to the surface of the adsorbent.
Groundwater is an indispensable source of water for drinking water supply, agriculture and industry worldwide. In arid and semi-arid regions, groundwater has seriously deteriorated in recent decades ...due to environmental changes, anthropogenic activities and marine intrusion. A total of 79 groundwater samples from the Nekor-Ghiss plain were sampled for major chemical ion analysis. These analyzes showed that the water samples were highly mineralized (>1,500 mg/L), with hardness (83.5% of the samples were very hard) and high concentrations of chemical elements, such as Cl
−
, Mg
2+
, Na
+
and SO
4
2-
. To assess the quality of water in the study area for irrigation and consumption purposes, we used the quality index (GWQI) as well as a multi-criteria analysis based on “geographic information system” by assigning a weight to the different water quality parameters. Also, Piper and Durov diagram was investigated. The results of the study were focused on the water quality parameters of the collected groundwater samples, such as the sodium adsorption rate (SAR), the percentage of soluble sodium (Na%), the Residual Sodium Carbonate (RSC) and Permeability Index (PI) Majority of water samples in the study area are suitable to be used for irrigation. Magnesium Risk (MH) and Kelley’s Ratio Kelly ratio. 51.9% unsuitable samples to 59.49% good samples for irrigation purposes. Monitoring the quality and quantity of groundwater is crucial for the effective and sustainable management of this valuable resource. According to the results obtained, it appears that 92% of all the samples are located in the domain of frequent recharge waters of limestone and dolomitic aquifers, namely, Ca-Mg-HCO
3
. About 8% of the samples measured have a composition of the Ca-Na-Mg-HCO
3
type.
In this work, we have studied and optimized the technique of the synthesis of hydroxyapatite by a new method called "dissolution/reprecipitation", with the aim of finding the appropriate operating ...conditions for the synthesis of apatitic nanoparticles. The optimum value of the size of the apatitic nanoparticles being 65 nm. The theoretical results presented by this experimental design have been verified: the experimental results are similar to the results estimated by this model. Scanning electron microscopy images confirm the morphology of apatitic nanoparticles and verify the validity of our mathematical modeling. Analysis by infrared spectroscopy and X-ray diffraction of the products obtained by the method shows that the final phases are pure and stoichiometric. The method of dissolving-reprecipitating apatitic nanoparticles has several advantages over other methods, such as purity and nanoscale sizes of the final phase. The new dissolution / reprecipitation method is a synthesis technique which makes it possible to prepare very pure hydroxyapatite nanoparticles without the intervention of precursors (salts) which generally generate impurities in the final product. The new method can then be used in the synthesis of apatitic biocomposites using biopolymers.
Greenhouse gasses are by-products of using fossil fuels to generate energy. It is known that climate change is caused by an increase in greenhouse gasses in the Earth's atmosphere. Solar energy is a ...renewable energy source that is an environmentally friendly resource for generating power. The photovoltaic (PV) system is a well-established technology for transforming solar energy into electric power. Sizing-decisions of a PV system is a strategic decision-making process that has a long-term impact on the project. This work proposes a multi-objective optimization (MOO) model for sizing-decisions of a grid-connected PV system. The objectives consider the economic aspect in terms of minimizing the project lifespan costs and non-economic aspects, including maximizing system reliability and reducing CO2 emissions. The sizing decisions are the number of PV panels, the amount of energy purchased from the main grid, and the amount of energy supplied to the main grid. In addition to a binary variable for an either-or decision, either purchase or supply from the grid. The model generates Pareto-optima to assist the decision-maker in assessing trade-offs between alternatives. A case study based on monthly demand for the residential area at King Fahd University of Petroleum & Minerals (KFUPM) is provided to clarify the practicality of the model. It is found that 1713 PV modules are required to meet annual demand at an annual cost of M$1.61 over 25 years.
•Sizing a PV system is a decision-making process that has a long-term impact.•Minimizing project costs, maximizing reliability, and reducing CO2 emissions.•The model assists the decision-maker in studying trade-offs between alternatives.•PV systems reduce CO2 emissions and secure a power supply under stable charges.
PurposeThis research integrates maintenance planning and production scheduling from a green perspective to reduce the carbon footprint.Design/methodology/approachA mixed-integer nonlinear programming ...(MINLP) model is developed to study the relation between production makespan, energy consumption, maintenance actions and footprint, i.e. service level and sustainability measures. The speed scaling technique is used to control energy consumption, the capping policy is used to control CO2 footprint and preventive maintenance (PM) is used to keep the machine working in healthy conditions.FindingsIt was found that ignoring maintenance activities increases the schedule makespan by more than 21.80%, the total maintenance time required to keep the machine healthy by up to 75.33% and the CO2 footprint by 15%.Research limitations/implicationsThe proposed optimization model can simultaneously be used for maintenance planning, job scheduling and footprint minimization. Furthermore, it can be extended to consider other maintenance activities and production configurations, e.g. flow shop or job shop scheduling.Practical implicationsMaintenance planning, production scheduling and greenhouse gas (GHG) emissions are intertwined in the industry. The proposed model enhances the performance of the maintenance and production systems. Furthermore, it shows the value of conducting maintenance activities on the machine's availability and CO2 footprint.Originality/valueThis work contributes to the literature by combining maintenance planning, single-machine scheduling and environmental aspects in an integrated MINLP model. In addition, the model considers several practical features, such as machine-aging rate, speed scaling technique to control emissions, minimal repair (MR) and PM.
•Develop maintenance model including parts quality, lead-time, and inspection errors.•Show that optimal cost increases steadily rate as mean degradation per time.•Find that replacement cost has the ...most significant impact on the optimal cost.•Perfect inspection value pays back and has considerable savings of up to 22.1%.
The upcoming industrial revolution 4.0 built on the internet of things, and prescriptive analytics paves the way for the spread of continuously monitored condition-based maintenance (CBM) in the industry. In the CBM implementations, it is essential to consider the impact of spare parts quality, lead-time, and inspection errors on maintenance cost and system availability. We propose a new maintenance model that incorporates the effects of these features in addition to the different cost factors, e.g., replacement cost, holding cost, and shortage cost. In a case study, we optimize our model by deciding on the degradation level at which a spare part is ordered. We show that a proper inspection of spare parts pays back up to 22% in maintenance cost savings as the spare parts' quality deteriorates. The vendor mean lead-time, the offered spare part price, and the mean degradation per time unit significantly impact the optimal maintenance cost. Finally, the costly detection processes of defective items installed in the system due to inspection errors have a limited cost reduction.
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