Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
16 result(s) for "Aydi, Abdelkarim"
Sort by:
Supercritical CO2 Extraction of Extracted Oil from Pistacia lentiscus L.: Mathematical Modeling, Economic Evaluation and Scale-Up
In this study, the extracted oil of Pistacia lentiscus L. the Tunis region was extracted using supercritical carbon dioxide (SC-CO2) extraction containing different major components in the oil such as α-pinene (32%) and terpinene-4-ol (13%). The investigation of the effect of different variables on the extraction yield with 5% level of confidence interval showed that the CO2 pressure was the main significant variable to influence the oil yield. In order to better understand the phenomena, three parameters were considered to adjust all parameters of broken and intact cell (BIC) model: grinding efficiency (G), the internal mass transfer parameter ( k S a 0 ), and the external mass transfer parameter ( k f a 0 ), which were estimated by experimental extraction curves to calculate the diffusion coefficient. From an economic point of view, we found out that the high cost of production of the extracted oil was due to the low mass of extracted oil obtained from this type of plant.
Exopolysaccharides from Lactiplantibacillus plantarum C7 Exhibited Antibacterial, Antioxidant, Anti-Enzymatic, and Prebiotic Activities
Previously, the exopolysaccharides produced by Lactiplantibacillus plantarum C7 isolated from the broiler intestine have been shown to possess probiotic potential. In this study, we highlighted the capacity of this strain to produce exopolysaccharide (EPS) endowed with several biological activities. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radical scavenging activities of EPS were found to be 30.4% and 68.165%, respectively, at 100 mg/mL. The ferrous reducing potential of EPS was measured to be 25.26%. Furthermore, EPS exhibited antibacterial effects against both Gram-negative and Gram-positive pathogens, including Escherichia coli ATCC 10536 and Bacillus cereus ATCC 11778, with inhibition zones of 22.5 ± 0.70 mm and 20 ± 1.41, respectively. On the other hand, the exopolysaccharide also exhibited excellent inhibitory activity against butyrylcholinesterase (BChE), achieving 70.99% inhibition at a concentration of 10 mg/mL. FTIR spectra were used to characterize functional groups in EPS. Our findings proved that EPS from Lactiplantibacillus plantarum C7 could be explored for various applications, particularly in the health and functional food sectors.
Heat Transfer Enhancement of MHD Natural Convection in a Star-Shaped Enclosure, Using Heated Baffle and MWCNT–Water Nanofluid
Fluids have played and still play a vital role in attaining an optimized output from industrial processes. However, due to technological advancement, fluids with high hydrothermal characteristics are required. In order to overcome these challenges, researchers have developed fluids with dispersed nanoparticles, which are recognized as nanofluids. Various types of nanoparticles can be added to base fluids to produce thermally enhanced liquids. Among these, the addition of multi-walled carbon nanotubes (MWCNTs) is considered the best due to the considerable enhancement of thermophysical properties and the stability of the solution. Thus, in the present investigation, an analysis of the heat transfer characteristics of an MWCNT–water nanofluid included in a star-shaped cavity equipped with a hot rectangular baffle is conducted. In addition, a uniform magnetic field is applied along the x-direction to oppose the convective flow generated by variations in density. Mathematical formulations under assumed boundary conditions and physical assumptions are established in the form of dimensionless PDEs. The finite-element-method-based software “COMSOL” is used to execute the numerical simulations. PARADISO is employed to resolve the developed non-linear system of equations. The effects of the governing parameters on the velocity and temperature fields are presented through streamlines and isotherms. The Nusselt number is evaluated to depict the impact of the addition of nanoparticles (MWCNTs) on the heat transfer enhancement. Changes in the horizontal and vertical components of velocity are also evaluated against the Rayleigh number and nanoparticle volume fraction via cutline representation.
A Sixth-Order Cubic B-Spline Approach for Solving Linear Boundary Value Problems: An In-Depth Analysis and Comparative Study
This research presents an efficient and highly accurate cubic B-spline method (CBSM) for solving second-order linear boundary value problems (BVPs). The method achieves sixth-order convergence, supported by rigorous error analysis, ensuring rapid error reduction with mesh refinement. The effectiveness of the CBSM is validated through four numerical examples, showcasing its accuracy, reliability, and computational efficiency, making it well-suited for large-scale problems. A comparative analysis with existing methods confirms the superior performance of the CBSM, positioning it as a practical and powerful tool for solving second-order BVPs.
Bioreactor Scale-Up and Kinetic Modeling of Lactic Acid and Biomass Production by Enterococcus faecalis SLT13 during Batch Culture on Hydrolyzed Cheese Whey
Kinetic modeling of biomass and lactic acid production by Enterococcus faecalis SLT13 have been developed during batch culture in M17 and Hydrolyzed Cheese Whey (HCW) in 2 L and 20 L bioreactors. The specific growth rate μmax was higher in 20 L bioreactor (1.09 h−1); however, the maximum specific lactic acid production rate qpmax and maximum specific sugar utilization rate qsmax were higher in 2 L bioreactor. Biomass and sugar utilization were affected by lactic acid inhibition in HCW. No effects of substrate inhibition have been observed. Substrate limitation of biomass has been observed on HCW in 20 L bioreactor; the substrate limitation constant for biomass Ksx was 4.229 g/L. Substrate limitation of sugar consumption has been observed on M17 in 2 L bioreactor; the substrate limitation constant for sugar consumption Kss was 2.73 g/L. Compared to experimental data, the model provided good predictions for biomass, sugar consumption, and lactic acid production.
Solubility, Solution Thermodynamics, and Preferential Solvation of Amygdalin in Ethanol + Water Solvent Mixtures
The equilibrium solubility of amygdalin in [ethanol (1) + water (2)] mixtures at 293.15 K to 328.15 K was reported. The thermodynamic properties (standard enthalpy ΔsolnH°, standard entropy ΔsolnS°, and standard Gibbs energy of solution ΔsolnG°) were computed using the generated solubility data via van’t Hoff and Gibbs equations. The dissolution process of amygdalin is endothermic and the driving mechanism in all mixtures is entropy. Maximal solubility was achieved in 0.4 mole fraction of ethanol at 328.15 K and the minimal one in neat ethanol at 293.15 K. Van’t Hoff, Jouyban–Acree–van’t Hoff, and Buchowski–Ksiazczak models were used to simulate the obtained solubility data. The calculated solubilities deviate reasonably from experimental data. Preferential solvation parameters of amygdalin in mixture solvents were analyzed using the inverse Kirkwood–Buff integrals (IKBI) method. Amygdalin is preferentially solvated by water in ethanol-rich mixtures, whereas in water-rich mixtures, there is no clear evidence that determines which of water or ethanol solvents would be most likely to solvate the molecule.
Hybrid Nano-Jet Impingement Cooling of Double Rotating Cylinders Immersed in Porous Medium
A cooling system with impinging jets is used extensively in diverse engineering applications, such as solar panels, electronic equipments, battery thermal management, textiles and drying applications. Over the years many methods have been offered to increase the effectiveness of the cooling system design by different techniques. In one of the available methods, nano-jets are used to achieve a higher local and average heat transfer coefficient. In this study, convective cooling of double rotating cylinders embedded in a porous medium is analyzed by using hybrid nano-jets. A finite element formulation of the thermo-fluid system is considered, while impacts of Reynolds number, rotational speed of the double cylinders, permeability of the porous medium and distance between the cylinders on the cooling performance are numerically assessed. Hybrid and pure fluid performances in the jet cooling system are compared. It is observed that the cooling performance improves when the rotating speed of the cylinder, permeability of the medium and jet Reynolds number are increased. The heat transfer behavior when varying the distance between the cylinders is different for the first and second cylinder. Higher thermal performances are achieved when hybrid nanofluid with higher nanoparticle loading is used. An optimization algorithm is used for finding the optimum distance and rotational speeds of the cylinders for obtaining an improved cooling performance, while results show higher effectiveness as compared to a parametric study. The outcomes of the present work are useful for the thermal design and optimization of the cooling system design for configurations encountered in electronic cooling, energy extraction and waste heat recovery.
Traditional Cereal Food as Container of Probiotic Bacteria “Lb. rhamnosus GG”: Optimization by Response Surface Methodology
This research paper aims at optimizing three parameters involved in solid state fermentation (SSF) using Lactobacillus rhamnosus GG (LGG) to improve a traditional cereal food “Bsissa” in order to elaborate a new probiotic fermented breakfast cereal. A Box-Behnken experimental design was used and the optimal fermentation conditions were liquid to solid ratio: 1.2 (vw−1), fermentation time: 12 h, and sucrose concentration: 10.48 g (100 g DM)−1. Under these conditions, the viable LGG cells, the free amino nitrogen content, and the total acidity were obtained to be 9.1 log10⁡(cfu g-1), 12.95 (mg g−1), and 6.46 (μmol g−1), respectively. After three weeks of refrigerated storage, the viability of LGG in the fermented Bsissa was 8.23 log10⁡(cfu g-1). This study shows a new possibility to make an acceptable nonfermented dairy product based mainly on cereals, leguminous plants, spices, and aromatic herbs, which are suitable substrates able to support the high probiotic viability.
Ethanolysis of Waste Cooking oils using KOH Catalyst
The transesterification of waste cooking oils (WCO) with ethanol was investigated by means of potassium hydroxide (KOH) as catalyst. This work aimed to study the influences of catalyst concentration, temperature, ethanol to WCO molar ratio, reaction time, and stirring rate on the biodiesel conversion. Gas chromatography (GC) was used during the process of transesterification to determine the evolution of ethyl esters concentration with time. Biodiesel with maximum yield was obtained (92.5%) when 2 wt% KOH, temperature of 75°C, and ethanol/oil molar ratio of 11:1 were utilized.
Cellulolytic Bacillus Strain: Production Optimization Using Wheat Bran under Solid-State Fermentation and Investigation of Its Probiotic Potential
Attention to the association of cellulolytic bacteria with probiotic potential as an additive in animal feeding has risen in the last decades. Such additive use in livestock feed is essential in improving animal health, growth, and production performances. This study was designed to identify probiotic characteristics and test the cellulolytic ability of Bacillus strains isolated from the dromedary gastrointestinal tract. Thus, thirty-two Bacillus strains were tested for their cellulolytic ability on cellulose Congo-red agar media. Among the isolates, only the strain D1B3 showed the largest degradation zone (2.4 cm) and was identified as Bacillus amyloliquefacians by 16S rRNA gene sequence analysis. Solid-state fermentation (SSF) retained this strain for cellulase and biomass production using wheat bran as a substrate. The fermentation was optimized through a central composite design, by exploring three factors: incubation temperature, moisture ratio, and pH. Biomass and cellulose enzyme activity were selected as responses and corresponding regression coefficients were calculated. The optimal parameters were: liquid-to-solid ratio (1.19%), pH buffer (6.2), and incubation temperature (36.99 °C) to obtain the highest level of biomass and cellulose enzyme activity reaching a value of 9.828 log CFU/g and 0.0144 g/L.min, respectively. The potentiality of Bacillus amyloliquefacians D1B3 as a probiotic was examined in vitro. It also showed antimicrobial activity against Pseudomonas aeruginosa 9027, Klebsiella pneumoniae, and Escherichia coli 10536. The isolate tolerates low pH and bile salt (0.3% Oxygall). The hydrophobicity and coaggregation abilities were 1.7% and 69.79%, respectively. The results indicated that Bacillus amyloliquefacians D1B3 could be a potential probiotic additive for improving in vitro fermentation of wheat bran and suggests the possibility of combining the probiotic attributes of this strain with its cellulolytic ability to enhance the rumen fermentation of animal feed.