Macro-sized Particles Research Articles

A highly sensitive β-AKBA-Ag-based fluorescent “turn off” chemosensor for rapid detection of abamectin in tomatoes

Abstract This study presents the synthesis of a sensitive AKBA-Based fluorescent “Turn off” chemosensor for rapid detection of abamectin residues in tomatoes. Silver nanoparticles were synthesized by using 3-O-acetyl-11-keto-β-boswellic acid (β-AKBA) by chemical reduction method. The characterization of AKBA-AgNPs was performed by UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The average particle size of NPs was found to be 46.2 ± 2 nm with lumps of macro-sized particles. TEM data further revealed that nanoparticles were polydispersed and spherical in shape and also show good stability at high temperatures and pH. The biosensing properties of nanoparticles were studied for the detection of abamectin residues in tomato samples. Abamectin a natural product derived from the bacterium Streptomyces avermitilis is effective against a wide range of pests. In sensing protocol 67 organic tomato samples were segregated into 34 (safe group, without a spray of abamectin) and 33 samples (as an unsafe group, sprayed with abamectin insecticide solution). Emission spectra of these sample solutions were measured in the wavelength range of 450–530 nm, excitation wavelength was fixed at 488 nm. The effect of minor wavelength variation for the discrimination and classification of the two groups was investigated by applying two chemometric methods including partial least square discriminant analysis and principal component analysis with projection. The mechanism of its interaction between the AKBA-Ag NPs and abamectin residue was also established through UV/visible, FTIR, and TEM microscopy. This newly synthesized nanoparticle was found to have excellent stability at variables, i.e., temperature, storage period, salt concentration, and pH. Therefore, the synthesized Ag NPs are potential candidates for biosensing applications against abamectin.

Utilization of mesoporous nano-silica as high-temperature water-based drilling fluids additive: Insights into the fluid loss reduction and shale stabilization potential

Optimally performing drilling fluids play a vital role in drilling operations. The demand for thermally stable drilling fluid in the oil and gas sector necessitates using advanced additives to create suitable formulations. This research study introduces the novel application of Mesoporous Nano-Silica (MNS) to enhance water-based drilling fluid's inhibitive, rheological, and fluid loss characteristics. MNS was synthesized by the sol-gel technique with Cetyltrimethylammonium Bromide (CTAB) for generating the pores. The hydrodynamic particle size of the synthesized MNS was 134.47 nm with a stable zeta potential of −32.2 meV. Brunauer-Emmett-Teller (BET) analyzer estimated the specific surface area to be 626 m2/g and the pore volume to be 0.3415 cm3/g. A comparative analysis of the drilling fluid properties is presented in which MNS was added to the fixed base formulation at varied concentrations (0.05, 0.1, 0.2, 0.5, and 1 wt%). Samples were subjected to hot rolling at 180 °C temperatures at 100 psi pressure for 16 h, evaluating the influence of thermal aging on the properties of the drilling fluid. The viscometric investigation was performed at 25 and 70 °C while the inhibitive properties were checked via shale recovery test and capillary suction timer. The filtration properties were examined at 100 psi and 500 psi pressure at 150 °C. The experimental findings reveal that MNS can substantially improve the thermal properties of water-based drilling fluids, maintaining rheological characteristics and drastically reducing fluid loss while imparting some inhibitive properties. Interestingly, after hot rolling the plastic viscosity of MNS-infused mud was 77% better than that of the base mud. Incorporating macro-sized particles and MNS nanoparticles into water-based drilling fluids can enhance its rheological properties, reduce filtrate loss, and improve shale inhibition characteristics which may be attributed to either the size effect or the synergistic influence of materials. Therefore, including MNS as a high-performance additive may contribute to advancing drilling operations in the petroleum industry, offering valuable insights for optimizing drilling fluid formulations.

Radiological Comparative Study Between Conventional and Nano Hydroxyapatite With Platelet-Rich Fibrin (PRF) Membranes for Their Effects on Alveolar Bone Density.

The entry of the concept of nanotechnologies into the field of biomaterials has improved the results of their use in regenerative therapies based on the principles of tissue engineering, due to its improvement of the physical properties of materials manufactured in this way, so it has become possible to produce particles of hydroxyapatite in nano sizes. This study will evaluate the efficacy of applying nanohydroxyapatite paste and platelet-rich fibrin (PRF) as a barrier membrane in comparison with traditionalhydroxyapatite (a powder consisting of macro-sized particles) and PRF as a barrier membrane in symmetrically extracted alveoli of the mandible. The research sample consisted of 40 lower alveoli (symmetrical) of the extracted teeth. The study samples were divided randomly into two groups. Group 1: A paste of nanohydroxyapatite with PRF as a barrier membrane was applied to one side of the extraction. Group 2: Hydroxyapatite powder with PRF as a barrier membrane was applied to the alveolus from the opposite side of Group 1 (the opposite side of the extraction). Three radiographs were performed by cone beam conventional tomography (CBCT) in three consecutive periods to conduct the radiological study (T0: immediately after extraction and grafting, T1: after three months, T2: after six months). The mean of the radiographic bone density of the hydroxyapatite powder group at time T0 is 824.36 HU with a standard deviation of ±277.29 HU, and at time T1 is 1119.93 HU with a standard deviation of ±306.93 HU, and at time T2 is 1074.14 HUwith a standard deviation of ±223.62 HU, with statistically significant differences when comparing the amount of change in radiographic bone density at time T0 and T1 withP < 0.05, and at time T0 and T2 with P < 0.05, but there were no significant differences when comparing the amount of change in radiographic bone density in T1 and T2 times with P > 0.05. The mean radiographic bone density of the nanohydroxyapatite paste group at time T0 is 629.88 HU with a standard deviation of ±193.64 HU, and at time T1 is 960.67 HU with a standard deviation of ±256.88 HU, and at time T2 is 743.87 HU with a standard deviation of ±180.96 HU, and in the time T0 and T1 with P < 0.05, and in the time T0 and T2 with P < 0.05, and in the time T1 and T2 with P < 0.05. Statistically, significant differences have been found between bone density change T1, T2in the nanohydroxyapatite paste group and bone density change T1, T2in the hydroxyapatite powder group P<0.05, which expresses a greater loss of density in the nanohydroxyapatite group, and thus the resorption of the bone graft and the placement of new bone tissue. Within the limits of our study, the results demonstrated that the use of traditional hydroxyapatite powder and nanohydroxyapatite paste increases the radiographic bone density, nanohydroxyapatite paste has a greater absorbency after 3 months compared with traditional hydroxyapatite powder which helps replace it by natural bone tissue.

A review on occurrence, characteristics, toxicology and treatment of nanoplastic waste in the environment.

Nanoplastics (NPs) have showed hotspot of discussion in recent years due to their impact in environment as a futuristic major pollutant in water, soil and air. In this correspondence review on the occurrence of nanoplastics and its effect at the environment as a waste have been overviewed and assimilated. It has the direct or indirect effect on aquatic and terrestrial geographical living beings due to its toxicity. The review revealed the major lacking in the field of analysis, database of contaminant quantity and legislative support to essential eradication on the existing imminent pollutant effects. A brief discussion about properties and characters of nanoplastics has been done. The environment exposed with macroplastics, microplastics and nanoplastics has abundantly contaminated the ecosystem surrounding it. Recent studies reveal that the major health effect by nanosize particles has mainly induced toxicity to the aquatic and terrestrial animals when compared to microsize particles and macrosize particles. The drastic effects and its toxicity in living ecosystem due to nanoplastics have been shown. The occurring waste is supposed to manage from environment by treating before entering into environment. The degradation methods for treatment of nanoplastics have been discussed in this review work.

Optical and Electron Microscopy for Analysis of Nanomaterials.

Not only isfabricationimportant for research in materials science, but also materials characterization and analysis. Special microscopes capable of ultra-high magnification are moreessential for observingand analyzingnanoparticles than for macro-size particles. Recently, electron microscopy (EM) and scanning probe microscopy (SPM) are commonly used for observing and analyzing nanoparticles. In this chapter, the basic principles of various techniques in optical and electronmicroscopy are described and classified. In particular, techniques such as transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are explained.

Single-atom catalysis: a new field that learns from tradition

Abstract Much of industrial chemical processing (in the petrochemicals industry, for example), and a great deal of laboratory chemical synthesis, involves catalysts that both lower the energy barrier to reaction and may help steer a reaction along a particular path. Traditionally, catalysts have come in two classes: heterogeneous, typically meaning that the catalyst is an extended solid; and homogeneous, where the catalyst is a small molecule that shares a solvent with the reactants. In heterogeneous catalysis, the reaction generally takes place on a surface, involving molecules attached there by covalent bonds. Homogeneous catalysts are often organometallic compounds, in which a metal atom or small cluster of atoms supplies the active site for reaction. In recent years, these distinctions have become somewhat blurred thanks to the advent of single-atom catalysis, where the catalytic site consists of a single atom (as in many homogeneous catalysts) attached to or embedded in a surface. The emergence of this field might be regarded as the logical conclusion of the use of ‘supported metal clusters’—small metal particles of nanometer scale and below, containing perhaps hundreds, tens or just a few atoms. It has became clear that such clusters can sometimes provide greater product selectivity and activity than macro-sized particles or powders of the same metal, partly because the active sites might be atoms at particular locations (such as edges and corners) in the nanoscale particles. By reducing their scale down to the level of single atoms, one can optimize these properties. At the same time, the potential uniformity of the atoms’ environments makes such catalysts more amenable to rational design and modeling to understand mechanism. This field represents an appealing blend of fundamental chemistry and physics—from the quantum-mechanical level upwards—and applied research aimed at producing many of the products vital to society, such as fuels and materials. Researchers in China have been strongly active in this field in recent years (see, for example, refs [1–5]). Jean Marie Basset of the King Abdullah University of Science and Technology in Thuwal, Saudi Arabia, is one of the leading practitioners in the area, and National Science Review spoke to him about the development and prospects of the field.

Design and evaluation of novel topical formulation with olive oil as natural functional active

Currently, the innovative skin research is focused on the development of novel topical formulations loaded with natural functional actives. The health benefits of olive oil are unsurpassed and many others are revealed as research studies allow the understanding of its unlimited properties. Olive oil has a protective toning effect on skin, but it is not transported effectively into its layers. Aiming the development of a cosmetic formulation for skin photoprotection and hydration, we have prepared and characterized macro-sized particles, made of a hydrogel polymer, loaded with olive oil. Alginate beads were uniform in shape, with minimal oil leakage, offering interesting prospects for encapsulation of lipophilic and poorly stable molecules, like olive oil. In vitro photoprotection and in vivo tolerance tests were in favor of this application. Thus, this study suggests that the incorporation of the olive oil-loaded particles into a cream formulation provides strong moisturizing properties and a photoprotective potential, when applied to healthy subjects.

Effective synthesis of biodiesel from Jatropha curcas oil using betaine assisted nanoparticle heterogeneous catalyst from eggshell of Gallus domesticus

The recovery of waste as feedstock away from organizational limitations corresponds to a prospective supplementary revenue stream for the organization. A novel waste eggshell of Gallus domesticus derived superbasic nanocatalyst was synthesized through betaine amphoteric surfactant-assisted decomposition, adsorption and precipitation processes. By varied the duration synthesis of gel mixture, the morphology transformation from liquid-solid interconnected macro-size particles to regular spheroidal nanoassemblies particles is detected. The surfactant at the liquid-solid interface facilitates the mono dispersion of nanoparticles by hindering growth of crystals. The average particle diameter of the produced superbasic nanocatalyst was in the range of 27–16 nm. The synthesized nanoparticle formation mechanism in the presence surfactant has also been addressed in this study. The catalytic activity of superbasic nanocatalyst was investigated for biodiesel production from crude Jatropha curcas oil (JCO) via glycerolysis and transesterification with methanol at atmospheric pressure. Artificial neural network (ANN) based on the genetic algorithm (GA) was applied for optimization of varied reaction parameters. It was observed that the reduction of acidity varied with varying reaction conditions. The highest fatty acid methyl ester (FAME) yield (97%) was obtained when the reaction was allowed to run at 60 °C for 300 min, while at 90 °C the maximal FAME yield of 98% was achieved after 120 min. The kinetic parameters of nanocatalyst were determined, and the reaction system followed pseudo first order kinetics. The results suggest that this two steps process using superbasic nanocatalyst affords a promising method to convert oils with high FFA level to biodiesel.

Facile fabrication of doubly porous polymeric materials with controlled nano- and macro-porosity

A critical overview of the different parameters affecting the porous features of doubly porous polymeric materials based on poly(2-hydroxyethyl methacrylate-co-ethylene glycol dimethacrylate) (poly(HEMA-co-EGDMA)) and designed via a double porogen templating approach is presented. A thorough investigation was accomplished so as to highlight the main advantages of the proposed double porogen approach which relied on the distinct and independent control of both porosity levels, i.e. nano- and macro-porosity. The nanoporosity level was produced via a phase separation phenomenon that occurred during the polymerization of the comonomers in the presence of various porogenic solvents. To generate the macroporosity, three straightforward and versatile strategies were implemented through the use of sodium chloride (NaCl) macro-sized particles. The first one implied the use of non-sintered NaCl particles that allowed for the creation of non-interconnected macropores. The other two strategies involved the sintering of NaCl particles prior to the generation of the poly(HEMA-co-EGDMA) network. In the latter case, NaCl particles were fused through two different methods, either through sintering at 730 °C or by Spark Plasma Sintering. Upon porogen removal, doubly porous PHEMA-based materials were obtained with macropores having NaCl particle imprints in the 100 μm order of magnitude, while the second porosity level laid within the 10 nm to 10 μm order of magnitude, as evidenced by mercury intrusion porosimetry and scanning electron microscopy, depending on the solvent structure, its volume proportion, and the cross-linker concentration in the polymerization feed. A full porous characterization was carried out in order to clearly understand the effect of such structural parameters on the porosity of the as-obtained doubly porous polymeric materials and their nanoporous counterparts.

Steam gasification of char from wood chips fast pyrolysis: Development of a semi-empirical model for a fluidized bed reactor application

This study, performed in the context of GAYA project, focuses on the development of a simple predictive model about steam gasification of char from woodchips fast pyrolysis. A semi-empirical model was developed through experiments in a macro thermogravimetric analyzer which owns the peculiar ability of fast heating, as well as to deal with macro-size particles and higher mass loads compared to conventional TGA. The experimental results show that gasification is controlled by chemical kinetics and internal transfer phenomena. During gasification, char particles can be considered as isothermal in a given range of temperatures and particle sizes, more likely for low values. The gasification model was based on the effectiveness factor, which involves the chemical kinetics and diffusion rate. The chemical kinetics were expressed by a classical Arrhenius law, whereas empirical expressions from mathematical fitting of the experimental data were established for the diffusion coefficient and surface function. The diffusion coefficient from this work is suspected to probably include supplementary rate limiting phenomena, apart from steam porous diffusion, such as H2 inhibition and/or the decrease of temperature within char particles because of the endothermic character of gasification. The model globally predicts with accuracy the gasification rate in typical operating conditions of a fluidized bed reactor. For its simplicity and reliability, this approach can be used for the modelling of char gasification in the conditions of interest.

Influence of Diameter on Surface Dispersive Free Energy of Polyethersulfone Nano-fibers

Nano-fibers have been applied in many fields because of their unique properties. Quantifying and characterizing the surface free energy and researching the influence of fiber diameters on surface free energies is important. In this paper, three kinds of polyethersulfone nano-fibers with the average diameter of 873, 567 and 254 nm were successfully fabricated by electrospinning at room temperature. The surface dispersive free energy of the three fibers and polyethersulfone (PES) macro-size particles were measured by inverse gas chromatography technique at 30, 40 and 50°C. It was found that the surface dispersive free energy decreased with decreasing fiber diameter. The rationality of the measured values of surface free energy was validated with a BSA adsorption experiment.

A Global Assessment of Gold, Titanium, Strontium and Barium Pollution Using Sperm Whales (Physeter Macrocephalus) As an Indicator Species

This study provides a global baseline for barium, gold, titanium and strontium as marine pollutants using the sperm whale (Physeter macrocephalus) as an indicator species. Barium, gold, titanium and strontium are metals that are little studied in marine environments. However, their recent emergence as nanomaterials will likely increase their presence in the marine environment. Moreover, nanosized particles are likely to exhibit toxic outcomes not seen in macrosized particles. Biopsies from free ranging sperm whales were collected from around the globe. Total barium levels were measured in 275 of 298 sperm whales tested for barium and collected from 16 regions around the globe. The global mean for barium was 0.93 +/- 0.2ug/g with a detectable range from 0.1 to 27.9ug. Total strontium levels were measurable in all 298 sperm whales producing a global mean level of 2.2 +/- 0.1ug/g and a range from 0.2 to 11.5ug/g. Total titanium levels were also measured in all 298 sperm whales producing a global mean level of 4.5 +/- 0.25ug/g with a range from 0.1 to 29.8ug/g. Total gold levels were detected in 50 of the 194 sperm whales collected from 16 regions around the globe. Detectable levels ranged from 0.1 to 2.3ug/g tissue with a global mean level equal to 0.2 +/- 0.02ug/g. Previous reports of these metals were much lower than the mean levels reported here. The likely explanation is location differences and consistent with this explanation, we found statistically significant variation among regions. These data provide an important global baseline for barium, gold, titanium and strontium pollution and will allow for important comparisons to be made over time to assess the impact of nanomaterials on whales and the marine environment.

Using sorbents to control heavy metals and particulate matter emission during solid fuel combustion

Some of the heavy metals in coal and wastes vaporize during combustion, concentrate in fine particulates, and emit with the flue gas into the atmosphere, to produce adverse effect on environment and health. This study first investigates the fate of the heavy metal species, especially Pb, Cd and Cr, known as semi-volatile, in various flue gases, especially in the presence of HCl and SO 2, by chemical equilibrium calculation, in which, Si and Ca were proposed as base sorbent materials to capture Pb, Cd and Cr. Then Si- and Ca-based compounds as well as waste materials used as sorbents were optimized to capture the heavy metals. Finally, the optimal sorbent was tested in actual burning of dried sewage sludge as solid fuel, to evaluate the effectiveness of the sorbent. Calculated results show that Cl increases the volatility of most heavy metals, while SO 2 enhances formation of condensed phases. Among the sorbents tested, kaolin appears most efficient to capture Pb and Cd. For sludge combustion with kaolin addition, both Pb and Cd were shifted from sub-micron to macro-sized particles, and accompanied by considerable decrease of 0.1 μm particles.

Nanoparticle fluidization and Geldart's classification

The behaviour of gas-particle interaction in a fluidized bed depends strongly on the size of the particles being fluidized. Fluidization characteristics of macro-sized particles, from several tens of microns to several millimetres, are well described by the Geldart [1973. Types of gas fluidization, Powder Technology 7, 285] classification. There is evidence that fluidization characteristics of nano-sized particles may be analysed by analogies to those of macro-sized particles. The aim of this paper is to look at whether the mechanism resulting in cohesive behaviour for macro-sized particles may be extended to nano-sized particles. Degussa Aerosil R974 powder, with a primary particle size of 12 nm, was fluidized using nitrogen in a cylindrical vessel, 50-mm-id and 900 mm in height. Characteristics of incipient fluidization are analysed in relation to variations in the initial packed bed conditions. Bed collapse experiments were performed and the results are used for assessing fluidization characteristics of the particles. It was found that nano-sized particles possess characteristics of both Group A and Group C of Geldart classification. Analysis shows that fluidization characteristics of nano-sized particles may be bridged to those of macro-sized particles through particle aggregation.