Flow and heat transfer property of Oldroyd-B-fluid-based nanofluids containing cylindrical particles are studied in a pipe with circular cross-section in the range of Reynolds number (Re) from 100 to 2000, Weissenberg number (We) from 0.1 to 2, particle aspect ratio (β) from 2 to 16 and particle volume concentration (Φ) from 0.1% to 2.5%. The motion equation of Oldroyd-B fluid with particles, the equation for probability density function of particle orientation and convection-diffusion equation for particles are solved numerically. The numerical method used in the simulation is validated by comparing with the available results. The effects of Re, We, β and Φ on the friction factor (f), Nusselt number (Nu) and ratio of energy performance evaluation criterion (PEC/PEC) for Oldroyd-B-fluid-based nanofluids to that for Oldroyd-B fluids are discussed. The results showed that the values of f and Nu of Oldroyd-B-fluid-based nanofluids are larger than that of water-based nanofluids and that of... [more]

New technologies for the conversion of biomass into high-value chemicals, including polymers and plastics, is a must and a challenge. The development of green processes in the last decade involved a continuous increase of the interest towards the synthesis of polymers using in vitro biocatalysis. Among the remarkable diversity of new bio-based polymeric products meeting the criteria of sustainability, biocompatibility, and eco-friendliness, a wide range of polyesters with shorter chain length were obtained and characterized, targeting biomedical and cosmetic applications. In this review, selected examples of such specialty polymers are presented, highlighting the recent developments concerning the use of lipases, mostly in immobilized form, for the green synthesis of ε-caprolactone co-polymers, polyesters with itaconate or furan units, estolides, and polyesteramides. The significant process parameters influencing the average molecular weights and other characteristics are discussed, re... [more]

Acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) are considered a well-known class of engineering thermoplastics due to their efficient use in automotive, 3D printing, and electronics. However, improvement in toughness, processability, and thermal stability is achieved by mixing together ABS and PC. The present study focuses on the understanding of surface mechanical characterization of acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) blends using nano-indentation. Polymer blends sheets with three different proportions of ABS/PC (75:25, 50:50, and 25:75) were fabricated via melt-processing and thermal press. Fourier transform infrared (FTIR) spectroscopy was performed to analyze the intermolecular interactions between the blends’ components. To understand the surface mechanical properties of ABS and PC blends, a sufficient number of nano-indentation tests were performed at a constant loading rate to a maximum load of 100 mN. Creeping effects were observed at the... [more]

Undoubtedly, polymers and composites are the most important materials in the late XXth and early XXIst century [...]

In order to study various influencing factors of spontaneous combustion accidents of sulfur-containing oil storage tanks, this paper constructed a two-dimensional model of the storage tank wall by COMSOL Multiphysics software. The proposed model takes temperature change trend as an observation index to explore the heat transfer process of the tank wall. By fitting the function curve of heat release with oxidation reaction temperature of sulfur corrosion products and comparing with constant heat sources, it is found that heat source intensity will affect the temperature growth trend of tank spontaneous combustion. In addition, the air convection heat transfer coefficient represents the interference degree of external environment to the spontaneous combustion heating process, and the wall heating rate decreases with the increase of air convection heat transfer coefficient. The different heat release rates in varying oxidation stages will lead to distinct temperature growth trends. The la... [more]

Reducing the pressure drop in biofilters is important for the reduction of the energy consumption of these devices. Usually, the pressure drop increases with time due to the biomass growth within the packing material. The aim of this study was to evaluate the aerodynamic processes in a laboratory-scale wavy lamellar (WL) plate-type biofilter equipped with a capillary system for humidifying the packing material. The packing material of a designed biofilter consisted of wavy polymer plates (WPP) vertically arranged next to each other. The pattern of arrangement of the plates allowed sufficiently large spaces, and therefore, the use of such structure had an impact on a decrease in the pressure drop of the biofilter. WPP were coated with three different kinds of materials, namely (I) wood fiber (WF), (II) non-woven caulking material (NWCM) and WF, and (III) linen material (LM) and WF. The results showed that the composition of the packing material influenced pressure drop of the biofilter.... [more]

Lung cancer is among the most prevalent and leading causes of death worldwide. The major reason for high mortality is the late diagnosis of the disease, and in most cases, lung cancer is diagnosed at fourth stage in which the cancer has metastasized to almost all vital organs. The other reason for higher mortality is the uptake of the chemotherapeutic agents by the healthy cells, which in turn increases the chances of cytotoxicity to the healthy body cells. The complex pathophysiology of lung cancer provides various pathways to target the cancerous cells. In this regard, upregulated onco-receptors on the cell surface of tumor including epidermal growth factor receptor (EGFR), integrins, transferrin receptor (TFR), folate receptor (FR), cluster of differentiation 44 (CD44) receptor, etc. could be exploited for the inhibition of pathways and tumor-specific drug targeting. Further, cancer borne immunological targets like T-lymphocytes, myeloid-derived suppressor cells (MDSCs), tumor-assoc... [more]

Essential oils are widely used as botanical insecticides rather than chemically synthesized pesticides which led to catastrophic effects on humans, the environment, and eutrophication. Here, encapsulation of four essential oils Basilicum ocimum, Cuminum cyminum, Origanum marjorana, and Matricaria chamomilla were utilized in the presence of 3% v/v ethanol, as anti-insect against Aphis craccivora and compared to traditional insecticides dinotefuran and pymetrozine. Different tools were used to characterize the prepared nanoemulsion such as TEM, SEM, and Zeta potential analyzer. Besides, selected B. ocimum and C. cyminum were analyzed by gas chromatography-mass GC/mass spectrometry. The results reveal that nanoemulsion exhibited considerable toxic activities against laboratory and field strains of cowpea aphid. In the toxicity bioassay test of essential oils, moderate mortality was observed at 10,000 mg/L against aphid with lethal concentration that kills 50% of insects (LC50) values of b... [more]

Using two methods (ferric reducing antioxidant power and radical scavenging activity), the total polyphenol content (Folin−Ciocalteu reagent) and polyphenol patterns (HPLC) in 10 commercial lager beer brands produced in Romania was determined. Samples bottled in glass, plastic and aluminium packages were analysed for each brand when available. Results have indicated considerable variations in the total and individual phenolic contents as well as antioxidant activity across beer brands. Gallic and feulic acids were the dominant phenolic compounds identified samples. The statistical analysis indicates a significant difference between the levels of antioxidant activity detected using DPPH and FRAP, for all three types of material considered. The statistical test ANOVA indicates that the polyphenol concentration is similar across all types of material.

In the treatment of industrial polluted sites and the construction of landfill sites, anti-pollution barriers are usually used to prevent the diffusion of pollutants. In this paper, the adsorption characteristics of Zn ions by the rock-bentonite anti-pollution barrier were observed by means of static equilibrium and dynamic adsorption tests. The experimental results showed that the adsorption of Zn by stone chips—bentonite was close to the nonlinear Freundlich and Langmuir models. When the concentration of Zn ion is constant, the adsorption capacity increases with the increase in temperature. At a certain temperature, the adsorption removal rate decreases with the increase in concentration. Further study found that the adsorption of Zn from mixed soil was mainly an ion exchange process, and the adsorption mode of Zn from mixed soil was controlled by both intra-particle diffusion and membrane diffusion. Zeta potential, X-ray diffraction (XRD) and The Fourier Transform Infrared spectrosc... [more]

The high moisture content present in sewage sludge hinders the use of sewage sludge in incineration or energy application. This limitation of moisture present in sewage sludge can be obviated by using the hydrothermal carbonization (HTC) process. In sewage sludge management, the HTC process requires less energy compared to other conventional thermo−chemical management processes. The HTC process produces energy-rich hydrochar products and simultaneously enables phosphorus recovery. This study investigates the influence of organic acids, inorganic acid, and alkali as additives on phosphorus transformation, yield, proximate analysis and the heating value of subsequently produced hydrochar. The analysis includes various process temperatures (200 °C, 220 °C, and 240 °C) in the presence of deionized water, acids (0.1 M and 0.25 M; H2SO4, HCOOH, CH3COOH), and alkali (0.1 M and 0.25 M; NaOH) solutions as feed water. The results show that phosphorus leaching into the process-water, hydrochar yi... [more]

Royal jelly is a natural substance secreted by worker honeybees that possesses antioxidant, anti-inflammatory, and other biological activities. The purpose of this study was to formulate microemulsions with incorporated Lithuanian royal jelly for possible ophthalmic delivery and to evaluate the quality of the microemulsions in vitro. The oil in water type microemulsions were prepared by the oil titration method, incorporating royal jelly, surfactant, co-surfactant, oil, and water. Physicochemical characteristics of the microemulsions and the quantity of 10-hydroxy-2-decenoic acid released in vitro were assessed. The in vitro assessment of prepared microemulsions formulations was performed with the Statens Seruminstitut rabbit cornea (SIRC) cell culture model. The results revealed that the droplet size of all microemulsion formulations was 67.88−124.2 nm and the polydispersity index was lower than 0.180. In the in vitro release study, the release of 10-hydroxy-2-decenoic acid depended o... [more]

The effects of water jet height and end dipping on cooling rate and hardenability in the Jominy end quench test were investigated to understand the Jominy test in more detail. Experimental tests were conducted under end dipping cooling condition as well as for specific water jet heights of 35, 65, and 100 mm. The thermal behavior and mechanical properties of the Jominy specimen with region were evaluated using thermocouples and hardness measurements, respectively. The effect of the water jet height on the thermal and hardness behaviors was not large; especially, the influence of water jet height was negligible when the water jet height was over 50 mm. These observations indicate that the uncertainty of the water jet height is not important during the standard Jominy end quench test. Meanwhile, during the standard Jominy test, we cannot neglect the heat flow along the radial direction of the specimen because the temperature difference between the center and surface area was not small; t... [more]

The ionic liquid A327H+Cl− is generated by reaction of the tertiary amine A327 (industrial mixture of tri-octyl and tri-decyl amines) and hydrochloric acid solutions. In this study, the extraction of Au(III) by A327H+Cl− ionic liquid under various variables, including metal and ionic liquid concentrations, was investigated. Results indicate that A327H+AuCl4− is formed by an exothermic (ΔH° = −3 kJ/mol) reaction in the organic solution. Aqueous ionic strength influences the formation constant values, and the specific interaction theory (SIT) was used to estimate the interaction coefficient between AuCl4− and H+. Gold (III) was stripped using thiocyanate media, and from the strip solutions, gold was precipitated as gold nanoparticles.

Palm olein-based diacylglycerol (POL-DAG) oil is a healthy product that is produced through enzymatic reaction and purification processes. However, POL-DAG oil easily solidifies at room temperature and crystallizes at high temperatures. The effect of different concentrations of sucrose stearate (1 and 10 g kg−1) added as a nonionic emulsifier, to POL-DAG oil containing 800 g kg−1 diacylglycerol, on its physical properties and flow behavior were investigated. The thermal properties of POL-DAG oil in melting, crystallization transition, and onset temperature were significantly decreased (p < 0.05) with the addition of emulsifiers. Besides, the incorporation of emulsifiers also significantly reduced (p < 0.05) the hardness of POL-DAG oil. Moreover, all POL-DAG oils with emulsifiers incorporated exhibited shear-thinning behavior, a low consistency coefficient (K) and a low apparent viscosity. The present study resolves the solidification issue and eases the pourability of POL-DAG oil... [more]

HCN-derived polymers are a heterogeneous group of complex substances synthesized from pure HCN; from its salts; from its oligomers, specifically its trimer and tetramer, amino-nalono-nitrile (AMN) and diamino-maleo-nitrile (DAMN), respectively; or from its hydrolysis products, such as formamide, under a wide range of experimental conditions. The characteristics and properties of HCN-derived polymers depend directly on the synthetic conditions used for their production and, by extension, their potential applications. These puzzling systems have been known mainly in the fields of prebiotic chemistry and in studies on the origins of life and astrobiology since the first prebiotic production of adenine by Oró in the early years of the 1960s. However, the first reference regarding their possible role in prebiotic chemistry was mentioned in the 19th century by Pflüger. Currently, HCN-derived polymers are considered keys in the formation of the first and primeval protometabolic and informatio... [more]

Lemongrass essential oil has many compounds appropriate for application in foods, cosmetics, and pharmaceutical products. Of these, citral is a high-value compound of interest to industry. This work aims to evaluate the use of vacuum fractional distillation to separate lemongrass essential oil compounds, producing essential oil fractions containing high citral content. The effect of process parameters, namely vacuum pressure, type column, and energy input, on the fractionation time, content, and recovery of citral in the fractions, was investigated. The fractionation of lemongrass oils successfully provided five fractions, i.e., fraction 1 (F1), fraction 2 (F2), fraction 3 (F3), fraction 4 (F4), and fraction 5 (F5). GC-MS (Gas Chromatography-Mass Spectrometry) spectra showed that the main compound contained in F1 and F2 fractions was β-myrcene (>70%). Meanwhile, F4 and F5 were the two main fractions for citral recovery. The optimal conditions of the fractional distillation system inclu... [more]

The growing worldwide demand for energy and resources, combined with the stringent environmental challenges and regulations, means that the efficient, cost-effective, and sustainable use of energy and material sources, including bio-based, has become increasingly important [...]

These days, environmental pollution, notably water pollution, has increasingly caused severe human health problems. The major water pollutants are heavy metals. MnFe2O4/GO nanocomposite was prepared in the current work via in situ method and tested to remove lead ion Pb2+ and neutral red (NR) dye from water. The prepared nanocomposite was characterized using different techniques, including X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectra, and vibrating sample magnetometer. The prepared nanocomposite showed high adsorption capacity toward Pb2+ and NR dye removal according to Langmuir fitting indicating the monolayer homogeneous adsorption of pollutants over the adsorbent surface and can be separated easily with an external magnet. The effect of different factors, including contact time, pH, initial concentration, and adsorbent dose on the adsorption, were also studi... [more]

Silver nanoparticles (AgNPs) find a wide range of use in many fields, and the biosynthesis of AgNPs via biological routines has recently gained currency. In this study, Bacillus licheniformis TT01 strain was isolated from quail feces collected in Vietnam and evaluated for its ability to synthesize AgNPs. Through visual confirmation and ultraviolet and visible (UV−Vis) spectrum analysis, we found that the biosynthesis of AgNPs was realized in the process in which biomass of B. licheniformis TT01 was incubated with AgNO3 solution. Obtained AgNPs were then assayed for antibacterial activity against three species of bacteria, namely Escherichia coli, Bacillus cereus and Ralstoniasolanacearum, showing better inhibitory action than the AgNO3 solution and the bacterial extracellular fluid. The minimum inhibitory concentration (MIC) of AgNP solution was 206 ppm against E. coli and R. solanacearum and 343.3 against B. cereus. X-ray diffraction (XRD) and transmission electron microscopy (TEM) re... [more]

In this work, we present a functionalization strategy of starch-poly(lactic acid) (PLA) blends with organic acids. Lactic and acetic acid were used as acid agents, and oleic acid was also included in the previous acids, with the aim of finding a synergy that thermodynamically benefits the products and provides hydrophobicity. The ratio of starch and sorbitol was 70:30, and the added acid agent replaced 6% of the plasticizer; meanwhile, the thermoplastic starch (TPS)−PLA blend proportion was 70:30 considering the modified TPS. The mixtures were obtained in a torque rheometer at 50 rpm for 10 min at 150 °C. The organic acids facilitated interactions between TPS and PLA. Although TPS and PLA are not miscible, PLA uniformly dispersed into the starch matrix. Furthermore, a reduction in the surface polarity was achieved, which enabled the wettability to reach values close to those of neat PLA (TPS−L-PLA increased by 55% compared to TPS−PLA). The rheological results showed a modulus similar t... [more]

Postharvest physiological deterioration (PPD) of fresh cassava roots limits their shelf-life to about 48 h. There is a demand for simple, cheap, and logistically feasible solutions for extending the shelf life of fresh cassava roots in industrial processes. In this study, three different types of bag materials were tested, namely woven polypropylene, tarpaulin, and jute as a potential storage solution for cassava roots with different levels of mechanical damage. Microclimate related to temperature, humidity, and carbon di-oxide (CO2) was monitored in order to understand the storage conditions for up to 12 days. The results showed that fresh cassava roots could be stored for 8 days, with minimal PPD and starch loss (2.4%). However, roots with significant mechanical damage in the form of cuts and breakages had a considerably shorter shelf life in the storage bag, compared to whole roots and roots with retained stalk (peduncle) where roots are connected to the main plant. Wetting of the r... [more]

One of the most important directions for environmental remediation is the effective removal of dyes and toxic heavy metals from water using newly fabricated nanoadsorbents. Here, magnetic Fe3O4 nanoparticles were combined with nitrogen-containing functional group polymers chitosan (CS) and polypyrrole (ppy) to synthesize a nanocomposite (polypyrrole@magnetic chitosan) useful for removing methyl orange (MO) and hexavalent chromium (Cr (VI)) from water. The physicochemical properties of the nanocomposite were determined using SEM, TEM, XRD, FT−IR, and TGA techniques. The effect of different factors on the adsorption system was studied including the contact time, pH, and the effect of co-existed ions. The kinetic study illustrated that the adsorption fit well with Langmuir isotherm. The maximum adsorption capacity of MO and Cr (VI) was found to be 95 and 105 mg/g, respectively. The reusability of the nanocomposite was studied for up to five cycles using 0.1 M NaOH as eluent with a slight... [more]

Molecules with poor aqueous solubility are difficult to formulate using conventional approaches and are associated with many formulation delivery issues. To overcome these obstacles, nanosuspension technology can be one of the promising approaches. Hence, in this study, the feasibility of mefenamic acid (MA) oral nanosuspension was investigated for pediatric delivery by studying the role of excipients and optimizing the techniques. Nanosuspensions of MA were prepared by adopting an antisolvent precipitation method, followed by ultrasonication with varying concentrations of polymers, surfactants, and microfluidics. The prepared nanosuspensions were evaluated for particle size, morphology, and rheological measures. Hydroxypropyl methylcellulose (HPMC) with varying concentrations and different stabilizers including Tween® 80 and sodium dodecyl sulfate (SLS) were used to restrain the particle size growth of the developed nanosuspension. The optimized nanosuspension formula was stable for m... [more]

MgH2 is one of the most promising hydrogen storage materials due to its high hydrogen storage capacity and favorable reversibility, but it suffers from stable thermodynamics and poor dynamics. In the present work, an intersected Y2O3/NiO hybrid with spherical hollow structure is synthesized. When introduced to MgH2 via ball-milling, the Y2O3/NiO hollow spheres are crushed into ultrafine particles, which are homogenously dispersed in MgH2, showing a highly effective catalysis. With an optimized addition of 10 wt% of the hybrid, the initial dehydrogenation peak temperature of MgH2 is reduced to 277 °C, lowered by 109 °C compared with that of the bare MgH2, which is further reduced to 261 °C in the second cycle. There is ca. 6.6 wt% H2 released at 275 °C within 60 min. For the fully dehydrogenation product, hydrogenation initiates at almost room temperature, and a hydrogenation capacity of 5.9 wt% is achieved at 150 °C within 150 min. There is still 5.2 wt% H2 desorbed after 50 cycles at... [more]