The reaction between apatite and sulfuric acid, which produces soluble phosphoric acid and insoluble phosphogypsum, is the main reaction taking place in a phosphoric acid plant. Nevertheless, there ...are side reactions’ involving some desirable and undesirable impurities. The present paper aimed to study and evaluate the performances and behavior of four grades of mineral phosphates coming from four different Moroccan mining sources (Khouribga, Youssoufia, Benguerir, and Bucraa) before their valorization to phosphoric acid via the wet dihydrate process. In the logic of preventing impurities’ impact and acting at source according to the first principle of green chemistry and using ratios established by different authors, the main effects of some impurities such as F
−
-
ions, CO
2
, SiO
2
, SO
3
, Al
2
O
3
, Fe
2
O
3
, MgO, K
2
O, and Na
2
O on phosphoric acid process performances (reactivity, sulfuric acid-specific consumption, phosphoric acid viscosity, foam formation, filterability, fouling, and corrosion) were identified and extensively investigated through leaching tests. Additionally, a practical thermal balance was established and showed that impurities could contribute 32% of the total heat released during the attack of apatite and consume 33% of dedicated sulfuric acid.
.
The onset of nanofluid convection in the presence of an externally applied magnetic field is investigated numerically based on the non-homogeneous Buongiorno’s mathematical model. In this study, we ...use the latest experimental correlations and powerful analytical models for expressing the thermo-physical properties of some electrically conducting nanofluids, such as copper-water, sliver-water and gold-water nanofluids, in which the Brownian motion and thermophoresis effects on slip flow in nanofluids are taken into account in this model (
i.e.
, two-phase transport model). In this paper, we assume that the nanofluid has Newtonian behavior, confined horizontally between two infinite impermeable boundaries and heated from below, in such a way that the nanoparticles tend to concentrate near the upper wall. Considering the basic state of the nanofluidic system, the linear stability theory has been successfully applied to obtain the principal stability equations, which are solved numerically for an imposed volumetric fraction of nanoparticles and no-slip impermeable conditions at the isothermal walls bounding the nanofluid layer. The linear boundary-value problem obtained in this investigation is converted into a pure initial-value problem, so that we can solve it numerically by the fourth-fifth-order Runge-Kutta-Fehlberg method. The generalized Buongiorno’s mathematical model proposed in this study allows performing a highly accurate computational analysis. In addition, the obtained results show that the stability of the studied nanofluidic system depends on several parameters, namely, the magnetic Chandrasekhar number
Q
, the reference value for the volumetric fraction of nanoparticles
ϕ
0
and the size of nanoparticles
d
p
. In this analysis, the thermo-hydrodynamic stability of the studied nanofluid is controlled through the critical thermal Rayleigh number
R
a
c
, which characterizes the onset of convection cells, whose size is
L
c
=
2
π
/
a
c
. Furthermore, the effects of various pertinent parameters on the critical stability parameters
R
a
c
and
a
c
are discussed in more detail through graphical and tabular illustrations, for three types of nanofluids including copper-water, sliver-water, and gold-water.
Polypropylene (PP)/clay nanocomposites were prepared by melt compounding with different grafted clay, such as montmorillonite, halloysite and sepiolite. These clays organically modified by grafting ...of two organosilanes namely 3-aminopropyltriethoxysilane (APTES) and vinyltrimethoxysilane (VTMS) were used as nanofillers for PP at different concentration (1–5 wt%). The physico-chemical properties of organosilane-modified clay-type were examined by various structural, thermal and morphological analysis routs. According to experimental data, all clays were successfully intercalaced using the silane molecules approved by the decline of the clay nano-particules size, modification of their chemical composition and the increase of their d-spacing. The efficiency of the silylation process as a good way to improve the matrix-fillers interaction was demonstrated by comparing the mechanical characteristics of the clays nanocomposites before and after grafting with organosilanes. Morphological and rheological properties of the PP/clay nanocomposites were also investigated in detail. In conclusion, it was found that the addition of the nano-organoclay allows improving the proprieties of silane grafted clays nanocomposites, which can endorse better interfacial adhesion between the organoclay and the polypropylene and their great spatial dispersion-distribution. The resulting PP/organosilane-grafted clay nanocomposites could be used by industry, or possible fields of application including automotive and construction industries.
Smart agriculture today uses a wide range of wireless communication technologies. Low Power Consumption Embedded Devices (LPCED), such as the Internet of Things (IoT) and Wireless Sensor Networks, ...make it possible to work over great distances at a reduced cost but with limited transferable data volumes. However, data management (DM) in intelligent agriculture is still not well understood due to the fact that there are not enough scientific publications available on this. Though data management (DM) benefits are factual and substantial, many challenges must be addressed in order to fully realize the DM’s potential. The main difficulties are data integration complexities, the lack of skilled personnel and sufficient resources, inadequate infrastructure, and insignificant data warehouse architecture. This work proposes a comprehensive architecture that includes big data technologies, IoT components, and knowledge-based systems. We proposed an AI-based architecture for smart farming. This architecture called, Smart Farming Oriented Big-Data Architecture (SFOBA), is designed to guarantee the system’s durability and the data modeling in order to transform the business needs for smart farming into analytics. Furthermore, the proposed solution is built on a pre-defined big data architecture that includes an abstraction layer of the data lake that handles data quality, following a data migration strategy in order to ensure the data’s insights.
The COVID-19 pandemic has been ongoing since its onset in late November 2019 in Wuhan, China. Understanding and monitoring the genetic evolution of the virus, its geographical characteristics, and ...its stability are particularly important for controlling the spread of the disease and especially for the development of a universal vaccine covering all circulating strains. From this perspective, we analyzed 30,983 complete SARS-CoV-2 genomes from 79 countries located in the six continents and collected from 24 December 2019, to 13 May 2020, according to the GISAID database. Our analysis revealed the presence of 3206 variant sites, with a uniform distribution of mutation types in different geographic areas. Remarkably, a low frequency of recurrent mutations has been observed; only 169 mutations (5.27%) had a prevalence greater than 1% of genomes. Nevertheless, fourteen non-synonymous hotspot mutations (>10%) have been identified at different locations along the viral genome; eight in ORF1ab polyprotein (in nsp2, nsp3, transmembrane domain, RdRp, helicase, exonuclease, and endoribonuclease), three in nucleocapsid protein, and one in each of three proteins: Spike, ORF3a, and ORF8. Moreover, 36 non-synonymous mutations were identified in the receptor-binding domain (RBD) of the spike protein with a low prevalence (<1%) across all genomes, of which only four could potentially enhance the binding of the SARS-CoV-2 spike protein to the human ACE2 receptor. These results along with intra-genomic divergence of SARS-CoV-2 could indicate that unlike the influenza virus or HIV viruses, SARS-CoV-2 has a low mutation rate which makes the development of an effective global vaccine very likely.
The present study investigates the feasibility of using polysaccharide enriched extracts (PEEs) from the red seaweed
Schizymenia dubyi
as coating materials in the preparation of controlled release ...triple superphosphate (TSP) fertilizers. Initially, the polysaccharide was isolated, extracted, and further characterized by gas chromatography and infrared analysis to determine its chemical composition and its partial structure. Results of chemical and spectroscopic analysis indicated that galactose, glucuronic acid, and glucose were the main components of the polysaccharide with a molecular weight of 2805 KDa. It can be suggested that this polysaccharide could be a sulfated glucuronogalactan. After that, the viscosity of the coating polysaccharide solution at different concentrations was conducted to determine the low and high polysaccharide concentrations that can be easily sprayed. After the spray coating process using different concentrations (1.8% and 2.5% w/v) and application cycles (from C1 to C4), the resulting coated fertilizer beads were chiefly characterized in terms of morphology, release kinetics in water and soil, and water retention properties. Results of the phosphorus release kinetics in water showed an effective effect for the slow release behaviour of the fertilizer. Increasing the concentration of the matrix additionally delays the release of P, and the best results were obtained with the formulation 2.5% -C4 which released 75% P after 5 to 7 days versus 2 days for the uncoated TSP. The same tendency was also recorded in soil release kinetics and weight losses. The soil water retention was also improved with the coated fertilizers, with over 4% more water retention than the uncoated fertilizers over 28 days. These findings showed that the polysaccharide-coated TSP fertilizer had multiple agronomic features and could be a promising candidate for various potential applications in agriculture.
Present study is designed for the synthesis, characterization and corrosion inhibition behavior of two diamine aromatic epoxy pre-polymers (DAEPs) namely, N
,N
,N
,N
-tetrakis (oxiran-2-ylmethyl) ...benzene-1,2-diamine (DAEP1) and 4-methyl-N
,N
,N
,N
-tetrakis (oxiran-2-ylmethyl) benzene-1,2-diamine (DAEP2) for carbon steel corrosion in acidic medium. Synthesized DAEPs were characterized using spectral (Nuclear magnetic resonance (
H NMR) and Fourier transform infrared-attenuated total reflection (FTIR-ATR)) techniques. Viscosity studies carried out at four different temperatures (20-80 °C) increase in temperature causes significant reduction in their viscosities. The anticorrosive properties of DAEPs differing in the nature of substituents, for carbon steel corrosion in 1 M HCl solution was evaluated using several experimental and computational techniques. Both experimental and computational studies showed that inhibitor (DAEP2) that contains electron releasing methyl (-CH
) showed higher protectiveness as compared to the inhibitor (DAEP1) without substituent (-H). Electrochemical results demonstrate that DAEPs act as reasonably good inhibitors for carbon steel in 1 M HCl medium and their effectiveness followed the sequence: DAEP2 (92.9%) > DAEP1 (91.7%). The PDP results show that the diamine aromatic epoxy pre-polymers molecules (DAEPs) act as mixed type inhibitors. Electrochemical study was also supported using scanning electron microscopy (SEM) method were significant improvement in the surface morphology of inhibited (by DAEPs) metallic specimens was obtained. Results derived from computational density functional theory (DFT) and molecular dynamics (MD) simulationsand studies were consistent with the experimental results derived from SEM, EIS and PDP electrochemical studies. Adsorption of the DAEPs obeyed the Langmuir adsorption isotherm model.
This study aims to develop new formulations for microbial fertilizers
Pseudomonas fluorescens Ms-01 (Pf)
and
Azosprillum brasilense
DSM1690 (
Ab
) using two kinds of clay minerals. The studied ...formulations were prepared as hybrid materials based on halloysite and alginate Ha-Ag or montmorillonite and alginate polymers Mt-Ag and were applied to the bacterial strains to develop low cost, efficient, and slow-release capsules. Their efficiency was evaluated in comparison with alginate Ag as the control. The produced capsules were spherical in shape and were chemically and physically characterized and further analyzed for their swelling ratios, soil biodegradability, release kinetics of microbial cells, and their survival stability over 3 months of storage under different conditions (room temperature vs 4 °C). The effect of the capsules on the growth of wheat plants was also investigated. Results showed that both formulations were able to preserve bacterial survival which reached 14.8 log CFU g
−1
after 3 months storage in the halloysite formulation. The swelling ratios were ranged between 61.5 ± 1.35% and 36.5 ± 5% for the montmorillonite and the halloysite formulations, respectively. The release kinetics revealed the slow-release capacity of the capsules mainly with the halloysite formulation which significantly released bacterial cells after 15 days of incubation in saline water (15.24 log CFU mL
−1
). The application of the capsules to wheat plants significantly increased root and shoot biomasses and nitrogen content in the roots. In conclusion, halloysite minerals seem to be more adapted as additive to alginate in microbial encapsulation.
Polysaccharides extracted from seaweeds can function as plant biostimulants. The aim of this study was to assess the effects of Polysaccharide Enriched Extracts (PEEs) obtained from 17 Moroccan ...seaweeds, on tomato seed germination and plant growth. Three concentrations (0.02, 0.05 and 0.1 mg mL
−1
) of PEEs were applied to tomato seeds to evaluate their effect on 3 germination parameters: germination percentage (GP), germination speed (GS) and mean germination time (MGT). Metabolomic analysis by GC–MS was subsequently performed on seedlings. In the second experiment, four PEEs concentrations (0.02, 0.05, 0.1 and 0.2 mg mL
−1
) were used as foliar spray or as soil application to tomato plants. Their growth parameters (number of leaves, shoot length, fresh and dry weight of stem and roots) and biochemical parameters (chlorophyll a and b) were measured. Results indicated a significant increase of GP and GS associated with a significant reduction of MGT of tomato seeds treated with 0.02 mg mL
−1
of PEEs obtained from
Gigartina
sp.,
Gigartina pistillata, Chondracanthus acicularis, Gelidium crinale, Schizymenia dubyi, Cystoseira. foeniculacea
and
Fucus spiralis.
Similar results were also obtained by application of higher PEEs concentration (0.1 mg mL
−1
) extracted from
Ulva rigida, Codium tomentosum, Codium decorticatum
and
Bifurcaria bifurcata.
Metabolomic analysis on seedlings detected the presence of some metabolites which could possibly be involved in seed germination enhancement or inhibition. The results of the second experiment showed that the same PEEs cited above at the same concentrations enhanced plant dry weight and chlorophyll a content except
Gigartina
sp., C
. foeniculacea
and
C. decorticatum
. Furthermore, soil application of PEEs was more effective in improving plant growth parameters than foliar application. The study shows the potential of PEEs from Moroccan seaweed to be used as biostimulants for a sustainable agriculture.
The reaction of hydroxymethyl pyrazole derivatives with one equivalent of the appropriate primary amine yields N-((1h-pyrazol-1-yl) methyl) pyrimidin-2-amine (L1), 2-(((1h-pyrazol-1-yl) methyl) ...amino) benzoic acid (L2), and ethyl 5-methyl-1-(((6-methyl-3-nitropyridin-2-yl) amino) methyl)-1h-pyrazole-3-carboxylate (L3). The structure of synthesized compounds (L1-L3) was identified by FT-IR, UV–visible, proton NMR spectroscopy, mass spectroscopy, and single crystal X-ray crystallography. The armed pyrazoles (L1-L3) were crystallized in the space groups C2/c, P21/n and P-1 for L1, L2, and L3 respectively. Crystallographic analysis revealed that N–H of the amine group and Nitrogen or Oxygen atoms are in-plane with the aromatic ring. The aminomethyl chain forms a distorted second plane. The angle between the two planes is observed to be 76.07° (N2–C7–N5–N19) for L1, 62.12° (N34–C63–N22–N35) for L2, 60.84° (N3–C8–N2–N1), and 0.41° (N1–C4–C3–O1/O2) for L3 was studied. Theoretical physical and chemical properties calculations have been performed on the studied armed pyrazoles (L1-L3) using three different programs: Petra, Osiris, & Molinspiration (POM). The geometric parameters of the optimized structure are in agreement with the experimental data obtained from the X-ray structures. The origin of the biological activity against breast cancer and microbes has also been confirmed.
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•The antitumor, antimicrobial activity of novel armed pyrazole derivatives was evaluated.•Identification of potential combined antimicrobial/antitumor pharmacophore sites by crystallographic analyses.•Computed quantum chemical descriptors based upon POM calculations have been used to correlate with biological activity.
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