Search results for: gas mixtures

Authors: F. Javier Benitez, Francisco J. Real, Juan Luis Acero, Francisco Casas

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Three emerging contaminants (amitriptyline hydrochloride, methyl salicylate and 2-phenoxyethanol) frequently found in waste-waters were selected to be individually degraded in ultra-pure water by the combined advanced oxidation process constituted by UV radiation and chlorine. The influence of pH, initial chlorine concentration and nature of the contaminants was firstly explored. The trend for the reactivity of the selected compounds was deduced: amitriptyline hydrochloride > methyl salicylate > 2-phenoxyethanol. A later kinetic study was carried out and focused on the specific evaluation of the first-order rate constants and the determination of the partial contribution to the global reaction of the direct photochemical pathway and the radical pathway. A comparison between the rate constant values among photochemical experiments without and with the presence of Cl₂ reveals a clear increase in the oxidation efficiency of the combined process with respect to the photochemical reaction alone. In a second stage, the simultaneous oxidation of mixtures of the selected contaminants in several types of water (ultrapure water, surface water from a reservoir, and two secondary effluents) was also performed by the same combination UV/Cl₂ under more realistic operating conditions. The efficiency of this combined system UV/Cl₂ was compared to other oxidants such as the UV/S₂O₈^2- and UV/H₂O₂ AOPs. Results confirmed that the UV/Cl₂ system provides higher elimination efficiencies among the AOPs tested.

Keywords: emerging contaminants, UV/chlorine advanced oxidation process, amitriptyline, methyl salicylate, 2-phenoxyethanol, chlorination, photolysis

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Authors: Erjola Reufi, Thomas Beer

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Plain, unreinforced concrete is a brittle material, with a low tensile strength, limited ductility and little resistance to cracking. In order to improve the inherent tensile strength of concrete there is a need of multi directional and closely spaced reinforcement, which can be provided in the form of randomly distributed fibers. Fiber reinforced concrete (FRC) is a composite material consisting of cement, sand, coarse aggregate, water and fibers. In this composite material, short discrete fibers are randomly distributed throughout the concrete mass. The behavioral efficiency of this composite material is far superior to that of plain concrete and many other construction materials of equal cost. The present experimental study considers the effect of steel fibers and polypropylene fiber on the modulus of elasticity of concrete. Hook end steel fibers of length 5 cm and 3 cm at volume fraction of 0.25%, 0.5% and 1.% were used. Also polypropylene fiber of length 12, 6, 3 mm at volume fraction 0.1, 0.25, and 0.4 % were used. Fifteen mixtures has been prepared to evaluate the effect of fiber on modulus of elasticity of concrete. Ultrasonic pulse velocity (UPV) and resonant frequency methods which are two non-destructive testing techniques have been used to measure the elastic properties of fiber reinforced concrete. This study found that ultrasonic wave propagation is the most reliable, easy and cost effective testing technique to use in the determination of the elastic properties of the FRC mix used in this study.

Keywords: fiber reinforced concrete(FRC), polypropylene fiber, resonance, ultrasonic pulse velocity, steel fiber

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Authors: Leonard D. Agana, Wendell Ace Dela Cruz, Arjan C. Lingaya, Bonifacio T. Doma Jr.

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The purpose of this paper is to study the predict the fuel performance parameters, which include drivability index (DI), vapor lock index (VLI), and vapor lock potential using distillation curve and Reid vapor pressure (RVP) of dual alcohol-gasoline fuel blends. Distillation curve and Reid vapor pressure were predicted using artificial neural networks (ANN) with macroscopic properties such as boiling points, RVP, and molecular weights as the input layers. The ANN consists of 5 hidden layers and was trained using Bayesian regularization. The training mean square error (MSE) and R-value for the ANN of RVP are 91.4113 and 0.9151, respectively, while the training MSE and R-value for the distillation curve are 33.4867 and 0.9927. Fuel performance analysis of the dual alcohol–gasoline blends indicated that highly volatile gasoline blended with dual alcohols results in non-compliant fuel blends with D4814 standard. Mixtures of low-volatile gasoline and 10% methanol or 10% ethanol can still be blended with up to 10% C3 and C4 alcohols. Intermediate volatile gasoline containing 10% methanol or 10% ethanol can still be blended with C3 and C4 alcohols that have low RVPs, such as 1-propanol, 1-butanol, 2-butanol, and i-butanol. Biography: Graduate School of Chemical, Biological, and Materials Engineering and Sciences, Mapua University, Muralla St., Intramuros, Manila, 1002, Philippines

Keywords: dual alcohol-gasoline blends, distillation curve, machine learning, reid vapor pressure

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Authors: Tahra Elobeid, Emmerich Berghofer

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The aim of this study is to find innovative approaches for the production of iron rich foods using natural iron sources. The vehicle used for fortification was sorghum whereas the iron fortificant was white bean. Fortified sorghum cookies were produced from five different mixtures; iron content, iron bioavailability, cookie texture and acceptability were measured. Cookies were prepared from the three fortified flours; 90% sorghum + 10% white bean (S9WB1), 75% sorghum + 25% white bean (S3WB1), 50% sorghum + 50% white bean (S1WB1) and 100% sorghum and 100% white bean. The functional properties gave good results in all the formulations. Statistical analysis of the iron content in the five different cookies showed that there was significant difference at the 95% confidence level (ANOVA). The iron content in all the recipes including the 100% sorghum improved, the increase ranging from 112% in 100% sorghum cookies to 476% in 100% white bean cookies. This shows that the increase in the amount of white bean used for fortification leads to the improvement of the iron content of cookies. The bioavailability of iron ranged from 21.3% in 100% sorghum to 28.6% in 100% white bean cookies. In the 100% sorghum cookies the iron bioavailability increased with reference to raw sorghum due to the addition of eggs. Bioavailability of iron in raw sorghum is 16.2%, therefore the percentage increase ranged from 5.1% to 28.6%. The cookies prepared from 10% white bean (S9WB1) scored the lowest 3.7 in terms of acceptability. They were the least preferred due to their somewhat soft texture. The 30% white bean cookies (S3WB1) gave results comparable to the 50% (S1WB1) and 100% white bean cookies. Cookies prepared with high percentage of white bean (50% and 100% white bean) gave the best results. Therefore cookie formulations from sorghum and white bean are successful in improving the iron status of anaemic individuals.

Keywords: sorghum, white bean, iron content, bioavailable iron, cookies

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Authors: Arghavan Kazemi, Hossein Radipour

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Microsilica (silica foam) is a byproduct of ferrosilicon production and silicon metal. Microsilica particles have a spherical shape, an average diameter of 0.15 µm, and a specific surface area of 15-25 m². g-¹. The overall density of this material is 150-700 kg.m-³. Many researchers have investigated the effect of adding microsilica on the flow properties of cement mixtures. This paper investigated the effect of adding microsilica on the flow behavior and injectability of silica-based paste. For this purpose, different percentages of microsilica have been used to prepare the paste. The rheometric test was performed on all the samples with different percentages of microsilica additives using an MCR300 rotary viscometer at a temperature of 70°C. In addition, the ability to inject pastes containing different amounts of microsilica at pressures of 25, 40, 50, and (bar) 60 at constant temperature and flow in a mold with dimensions of 80 × 80 × 0.5 mm³ has been investigated. Then, the effect of microsilica addition on the strength, porosity percentage, and leachability of the sintered core was studied. The results show that the rheological behavior of the paste is pseudoplastic; also, the silane index decreases with the increase in the percentage of microsilica addition, and the viscosity increases. On the other hand, the addition of microsilica has led to the appearance of thixotropic in the paste. By increasing the amount of microsilica, the injectability has significantly improved at low pressures. The strength of the sintered core increases with the increase of microsilica and the amount of remaining porosity and leachability decreases.

Keywords: microsilica, rheological behavior, injectability, injection molding, silica-based ceramic cores, leachability

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Authors: Rudzani Lusunzi, Frans Waanders, Elvis Fosso-Kankeu, Robert Khashane Netshitungulwana

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The Sabie Goldfield has a history of gold mining dating back more than a century. Acid mine drainage (AMD) from the Nestor mine tailings storage facility (MTSF) poses a serious threat to the nearby ecosystem, specifically the Sabie River system. This study aims at developing mitigation measures for the AMD emanating from the Nestor MTSF using materials from the Glynns Lydenburg MTSF. The Nestor MTSF (NM) and the Glynns Lydenburg MTSF (GM) each provided about 20 kg of bulk composite samples. Using samples from the Nestor MTSF and the Glynns Lydenburg MTSF, two mixtures were created. MIX-A is a mixture that contains 25% weight percent (GM) and 75% weight percent (NM). MIX-B is the name given to the second mixture, which contains 50% AN and 50% AG. The same static test, i.e., acid–base accounting (ABA), net acid generation (NAG), and acid buffering characteristics curve (ABCC) was used to estimate the acid-generating probabilities of samples NM and GM for MIX-A and MIX-B. Furthermore, the mineralogy of the Nestor MTSF samples consists of the primary acid-producing mineral pyrite as well as the secondary minerals ferricopiapite and jarosite, which are common in acidic conditions. The Glynns Lydenburg MTSF samples, on the other hand, contain primary acid-neutralizing minerals calcite and dolomite. Based on the assessment conducted, materials from the Glynns Lydenburg are capable of neutralizing AMD from Nestor MTSF. Therefore, the alkaline tailings materials from the Glynns Lydenburg MTSF can be used to rehabilitate the acidic Nestor MTSF.

Keywords: Nestor Mine, acid mine drainage, mitigation, Sabie River system

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Authors: Florin Leon, Silvia Curteanu

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Developing complete mechanistic models for polymerization reactors is not easy, because complex reactions occur simultaneously; there is a large number of kinetic parameters involved and sometimes the chemical and physical phenomena for mixtures involving polymers are poorly understood. To overcome these difficulties, empirical models based on sampled data can be used instead, namely regression methods typical of machine learning field. They have the ability to learn the trends of a process without any knowledge about its particular physical and chemical laws. Therefore, they are useful for modeling complex processes, such as the free radical polymerization of methyl methacrylate achieved in a batch bulk process. The goal is to generate accurate predictions of monomer conversion, numerical average molecular weight and gravimetrical average molecular weight. This process is associated with non-linear gel and glass effects. For this purpose, an adaptive sampling technique is presented, which can select more samples around the regions where the values have a higher variation. Several machine learning methods are used for the modeling and their performance is compared: support vector machines, k-nearest neighbor, k-nearest neighbor and random forest, as well as an original algorithm, large margin nearest neighbor regression. The suggested method provides very good results compared to the other well-known regression algorithms.

Keywords: batch bulk methyl methacrylate polymerization, adaptive sampling, machine learning, large margin nearest neighbor regression

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Authors: Khamael M. Abualnaja, Lidija Šiller, Ben R. Horrocks

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Surface enhanced Raman spectroscopy (SERS) of Silicon nano crystals (SiNCs) were obtained using two different laser excitations: 488 nm and 514.5 nm. Silver nano particles were used as plasmonics metal nano particles due to a robust SERS effect that observed when they mixed with SiNCs. SiNCs have been characterized by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the SiNCs are crystalline with an average diameter of 65 nm and FCC lattice. Silver nano particles (AgNPs) of two different sizes were synthesized using photo chemical reduction of AgNO3 with sodium dodecyl sulfate (SDS). The synthesized AgNPs have a polycrystalline structure with an average particle diameter of 100 nm and 30 nm, respectively. A significant enhancement in the SERS intensity was observed for AgNPs100/SiNCs and AgNPs30/SiNCs mixtures increasing up to 9 and 3 times respectively using 488 nm intensity; whereas the intensity of the SERS signal increased up to 7 and 2 times respectively, using 514.5 nm excitation source. The enhancement in SERS intensities occurs as a result of the coupling between the excitation laser light and the plasmon bands of AgNPs; thus this intense field at AgNPs surface couples strongly to SiNCs. The results provide good consensus between the wavelength of the laser excitation source and surface plasmon resonance absorption band of silver nano particles consider to be an important requirement in SERS experiments.

Keywords: silicon nanocrystals (SiNCs), silver nanoparticles (AgNPs), surface enhanced raman spectroscopy (SERS)

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Authors: Ubani Onyedikachi, Atagana Harrison Ifeanyichukwu, Thantsha Mapitsi Silvester

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Components of oil sludge (PAHs) are known cytotoxic, mutagenic and potentially carcinogenic compounds also bacteria and fungi have been found to degrade PAHs to innocuous compounds. This study is aimed at measuring the effect of pig, cow, horse and poultry manures on the degradation in selected PAHs present in oil sludge. Soil spiked with oil sludge was co-composted differently with each manure in a ratio of 2:1 (w/w) spiked soil: manure and wood-chips in a ratio of 2:1 (w/v) spiked soil: wood-chips. Control was set up similar as the one above but without manure. The mixtures were incubated for 10 months at room temperature. Compost piles were turned weekly and moisture level was maintained at between 50% and 70%. Moisture level, pH, temperature, CO2 evolution and oxygen consumption were measured monthly and the ash content at the end of experimentation. Highest temperature reached was 27.5 °C in all compost heaps, pH ranged from 5.5 to 7.8 and CO2 evolution was highest in poultry manure at 18.78μg/dwt/day. Microbial growth and activities were enhanced; bacteria identified were Bacillus, Arthrobacter and Staphylococcus species. Percentage reduction in PAHs was measured using automated soxhlet extractor with Dichloromethane coupled with gas chromatography/mass spectrometry (GC/MS). Results from PAH measurements showed reduction between 77% and 99%. Co-composting of spiked soils with animal manures enhanced the reduction in PAHs.

Keywords: animal manures, bioremediation, co-composting, oil refinery sludge, PAHs

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Authors: Ergün Şakalar, Şeyma Özçirak Ergün

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Pistachio nuts, the fruits of the pistachio tree (Pistacia vera), are edible tree nuts highly valued for their organoleptic properties. Pistachio nuts used in snack foods, chocolates, baklava, meat products, ice-cream industries and other gourmet products as ingredients. Undeclared pistachios may be present in food products as a consequence of fraudulent substitution. Control of food samples is very important for safety and fraud. Mix of pistachio, peanut (Arachis hypogaea), pea (Pisum sativum L.) used instead of pistachio in food products, because pistachio is a considerably expensive nut. To solve this problem, a sensitive polymerase chain reaction PCR has been developed. A real-time PCR assay for the detection of pea, peanut and pistachio in baklava was designed by using EvaGreen fluorescence dye. Primers were selected from powerful regions for identification of pea, peanut and pistachio. DNA from reference samples and industrial products were successfully extracted with the GIDAGEN® Multi-Fast DNA Isolation Kit. Genomes were identified based on their specific melting peaks (Mp) which are 77°C, 85.5°C and 82.5°C for pea, peanut and pistachio, respectively. Homogenized mixtures of raw pistachio, pea and peanut were prepared with the ratio of 0.01%, 0.1%, 1%, 10%, 40% and 70% of pistachio. Quantitative detection limit of assay was 0.1% for pistachio. Also, real-time PCR technique used in this study allowed the qualitative detection of as little as 0.001% level of peanut DNA, 0,000001% level of pistachio DNA and 0.000001% level of pea DNA in the experimental admixtures. This assay represents a potentially valuable diagnostic method for detection of nut species adulterated with pistachio as well as for highly specific and relatively rapid detection of small amounts of pistachio in food samples.

Keywords: pea, peanut, pistachio, real-time PCR

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Authors: Nouria Bouchikhi, Soufiane Bedjaoui, C. Tewfik Bouchaour, Lamia Alachaher Bedjaoui, Ulrich Maschke

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Swelling properties and phase diagrams of binary systems composed of liquid crystalline networks and a low molecular mass liquid crystal (LMWLC) have been investigated. The networks were prepared by ultraviolet (UV) irradiation of reactive mixtures including a monomer, a cross-linking agent and a photo-initiator. These networks were prepared using two cross-linking agents: 1,6 hexanedioldiacrylate (HDDA) and a mesogenic acrylic acid 6-(4’-(6-acryloyloxy-hexyloxy) biphenyl-4-yl oxy) hexyl ester (AHBH). The obtained dry networks were characterized by differential scanning calorimetry, and immersed in an excess of a LMWLC solvent 4-cyano-4’-pentylbiphenyl (5CB), forming polymer gels. A detailed study by polarized optical microscopy allowed to determine the swelling degree of the gels and to follow the phase behavior of the solvent inside the polymer matrix in a wide range of temperature. It has been found that the gels undergo a sharp decrease of their swelling degree in response to an infinitesimal change of temperature. This finding adds new and interesting aspects on the actuators applications. We have subsequently explored the effect of different parameters on volume phase transition of these liquid crystalline materials. Such as the cross-linking density (CD), a nature of cross-linking agent and the photo initiator concentration.

Keywords: cross-linking density, liquid crystalline elastomers, phase diagrams, swelling

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Authors: N. G. Margiani, I. G. Kvartskhava, G. A. Mumladze, Z. A. Adamia

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Chemical doping with different elements and compounds at various amounts represents the most suitable approach to improve the superconducting properties of bismuth-based superconductors for technological applications. In this paper, the influence of partial substitution of Sr(BO₂)₂ for SrO on the phase formation kinetics and transport properties of (Bi,Pb)-2223 HTS has been studied for the first time. Samples with nominal composition Bi_1.7Pb_0.3Sr_2-xCa₂Cu₃O_y[Sr(BO₂)₂]_x, x=0, 0.0375, 0.075, 0.15, 0.25, were prepared by the standard solid state processing. The appropriate mixtures were calcined at 845 ^oC for 40 h. The resulting materials were pressed into pellets and annealed at 837 ^oC for 30 h in air. Superconducting properties of undoped (reference) and Sr(BO₂)₂-doped (Bi,Pb)-2223 compounds were investigated through X-ray diffraction (XRD), resistivity (ρ) and transport critical current density (J_c) measurements. The surface morphology changes in the prepared samples were examined by scanning electron microscope (SEM). XRD and J_c studies have shown that the low level Sr(BO₂)₂ doping (x=0.0375-0.075) to the Sr-site promotes the formation of high-T_c phase and leads to the enhancement of current carrying capacity in (Bi,Pb)-2223 HTS. The doped sample with x=0.0375 has the best performance compared to other prepared samples. The estimated volume fraction of (Bi,Pb)-2223 phase increases from ~25 % for reference specimen to ~70 % for x=0.0375. Moreover, strong increase in the self-field J_c value was observed for this dopant amount (J_c=340 A/cm²), compared to an undoped sample (J_c=110 A/cm²). Pronounced enhancement of superconducting properties of (Bi,Pb)-2223 superconductor can be attributed to the acceleration of high-T_c phase formation as well as the improvement of inter-grain connectivity by small amounts of Sr(BO₂)₂ dopant.

Keywords: bismuth-based superconductor, critical current density, phase formation, Sr(BO₂)₂ doping

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Authors: Sadegh Sadeghi, Negar Shabani

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From a thermal point of view, zeotropic mixtures are likely to be more efficient than azeotropic fluids in low-temperature thermodynamic cycles due to their suitable boiling characteristics. In this study, performance of a low-temperature Kalina cycle with R717/water working fluid used in different existing power plants is mathematically investigated. To analyze the behavior of the cycle, mass conservation, energy conservation, and exergy balance equations are presented. With regard to the similarity in molar mass of R717 (17.03 gr/mol) and water (18.01 gr/mol), there is no need to alter the size of Kalina system components such as turbine and pump. To optimize the cycle energy and exergy efficiencies simultaneously, a constrained multi-objective optimization is carried out applying an Artificial Bee Colony algorithm. The main motivation behind using this algorithm lies on its robustness, reliability, remarkable precision and high–speed convergence rate in dealing with complicated constrained multi-objective problems. Convergence rates of the algorithm for calculating the optimal energy and exergy efficiencies are presented. Subsequently, due to the importance of exergy concept in Kalina cycles, exergy destructions occurring in the components are computed. Finally, the impacts of pressure, temperature, mass fraction and mass flow rate on the energy and exergy efficiencies are elaborately studied.

Keywords: artificial bee colony algorithm, binary zeotropic mixture, constrained multi-objective optimization, energy efficiency, exergy efficiency, Kalina cycle

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Authors: Masek A., Diakowska K., Zaborski M.

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Polymeric materials have found their use almost in every branch of industry worldwide. Most of them constitute so-called “petropolymers" obtained from crude oil. However literature information sounds a warning that its global sources are running out. Thus, it seems that one should search for polymeric materials from renewable raw materials belonging to the group of green polymers. Therefore on account of environmental protection and the issue of sustainable technologies, nowadays greater and greater achievements have been observed in the field of green technology using engineering sciences to develop composite materials. The main aim of this study was to research what is the influence of biofillers on the properties. We used biofillers like : cellulose with different length of fiber, cellulose UFC100, silica and montmorillonite. In our research, we reported on biodegradable composites exhibitingspecificity properties by melt blending of polylactide (PLA), one of the commercially available biodegradable material, and epoxidized natural rubber (ENR) containing 50 mol.%epoxy group. Blending hydrophilic natural polymers and aliphatic polyesters is of significant interest, since it could lead to the development of a new range of biodegradable polymeric materials. We research the degradation of composites on the basis epoxidized natural rubber and poly(lactide). The addition of biofillers caused far-reaching degradation processes. The greatest resistance to biodegradation showed a montmorillonite-based mixtures, the smallest inflated cellulose fibers of varying length.The final aim in the present study is to use ENR and poly(lactide) to design composite from renewable resources with controlled degradation.

Keywords: renewable resources, biopolymer, degradation, polylactide

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Authors: Elin Julianti, Marlia Singgih, Masayoshi Arai, Jianyu Lin, Masteria Yunovilsa Putra, Muhammad Azhari, Agnia S. Muharam

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The search for a source of new medicinal compounds with anticancer activity from natural products has become important to resolve the ineffectiveness problem of pancreatic cancer therapy. Fungal marine microorganisms are prolific sources of bioactive natural products. In this present study, the ethyl acetate extract of cultured broth of Trichoderma longibrachiatum marine sponge-derived fungi exhibited selective cytotoxicity against human pancreatic carcinoma PANC-1 cells cultured under glucose-deficient conditions (IC50 = 98,4 µg/mL). The T. longibrachiatum was fermented by the static method at room temperature for 60 days. The culture broth was extracted using ethyl acetate by liquid-liquid extraction method. The liquid-liquid extraction was conducted toward the ethyl extract by using 90% MeOH-H₂O and n-|Hexane as a solvent. The extract of 90% MeOH-H₂O was fractionated by liquid extraction using by C₁₈ reversed-phase vacuum flash chromatography using mixtures of MeOH-H₂O, from 50:50 to 100:0, and 1% TFA MeOH as the eluents to yield six fractions. The fraction 2 (MeOH-H2O, 70:30) and fraction 3 (MeOH-H2O, 80:20) showed moderate cytotoxicity with IC50 value of 119.3 and 274.7 µg/mL, respectively. Fraction 4 (MeOH-H₂O, 90:10) showed the highest cytotoxicity activity with IC₅₀value of < 10 µg/mL. The chemical compounds of the fractions that are responsible for cytotoxic activity are potent for further investigation.

Keywords: cytotoxic activity, trichoderma longibrachiatum, marine-derived fungi, PANC-1 cell line

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Authors: C. Paglia, C. Mosca

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Synthetic resin floorsare often used in sport infrastructure. These organic materials are often in contact with a bituminous substrate, which in turn is placed on the ground. In this work, the damage of a basket resin field surface was characterized by means of visual inspection, optical microscopy, resin thickness measurements, adhesion strength, water vapor transmission capacity, capillary water adsorption, granulometry of the bituminous conglomerate, the surface properties, and the water ground infiltration speed. The infiltration speed indicates water pemeability. This was due to its composition: clean sand mixed with gravel. Relatively good adhesion was present between the synthetic resin and the bituminous layer. The adhesion resistance of the bituminous layer was relatively low. According to the required bitumoniousasphalt-concrete mixes AC 11 S, the placed material was more porous. Insufficient constipation was present. The spaces values were above the standard limits, while the apparent densities were lower compared to the conventional AC 11 mixtures. The microstructure outlines the high permeability and porosity of the bituminous layer. The synthetic resin wasvapourproof and did not exhibit capillary adsorption. It exhibited a lower thickness as required, and no multiple placing steps were observed. Multiple cavities were detected along with the interface between the bituminous layer and the resin coating with no intermediate layers. The layer for the pore filling in the bituminous surface was not properly applied. The swelling bubbles on the synthetic pavement were caused by the humidity in the bituminous layer. Water or humidity were present prior to the application of the resin, and the effect was worsened by the upward movement of the water from the ground.

Keywords: resin, floor, damage, durability

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Authors: Manuel Rosales, Francisco Agrela, Julia Rosales

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The development of concrete pavements that include recycled waste with active and predictive safety features is a possible approach to mitigate the harmful impacts of the construction industry, such as CO2 emissions and the consumption of energy and natural resources during the construction and maintenance of road infrastructure. This study establishes the basis for formulating new smart materials for concrete pavements and carrying out the in-situ implementation of an experimental road section. To this end, a comprehensive recycled pavement solution is developed that combines eco-hybrid cement made with 25% mixed recycled aggregate powder (pMRA) and biomass bottom ash powder (pBBA) and a 30% substitution of natural aggregate by MRA and BBA. This work is grouped in three lines. 1) construction materials with high rates of use of recycled material, 2) production processes with efficient consumption of natural resources and use of cleaner energies, and 3) implementation and monitoring of road section with sustainable concrete made from waste. The objective of this study is to ensure satisfactory rheology, mechanical strength, durability, and CO2 capture of pavement concrete manufactured from waste and its subsequent application in real road section as well as its monitoring to establish the optimal range of recycled material. The concrete developed during this study are aimed at the reuse of waste, promoting the circular economy. For this purpose, and after having carried out different tests in the laboratory, three mixtures were established to be applied on the experimental road.

Keywords: biomass bottom ash, construction and demolition waste, recycled concrete pavements, full-scale experimental road, monitoring

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Authors: Samara A. Testoni, Vander F. Melo, Lorna A. Dawson, Fabio A. S. Salvador

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Soil traces are useful as forensic evidence due to their potential to transfer and adhere to different types of surfaces on a range of objects or persons. The great variability expressed by soil physical, chemical, biological and mineralogical properties show soil traces as complex mixtures. Soils are continuous and variable, no two soil samples being indistinguishable, nevertheless, the complexity of soil characteristics can provide powerful evidence for comparative forensic purposes. This work aimed to establish a Standard Operating Procedure (SOP) for forensic soil analysis in Brazil. We carried out a simulated crime scene with double blind sampling to calibrate the sampling procedures. Samples were collected at a range of locations covering a range of soil types found in South of Brazil: Santa Candida and Boa Vista, neighbourhoods from Curitiba (State of Parana) and in Guarani and Guaraituba, neighbourhoods from Colombo (Curitiba Metropolitan Region). A previously validated sequential analyses of chemical, physical and mineralogical analyses was developed in around 2 g of soil. The suggested SOP and the sequential range of analyses were effective in grouping the samples from the same place and from the same parent material together, as well as successfully discriminated samples from different locations and originated from different rocks. In addition, modifications to the sample treatment and analytical protocol can be made depending on the context of the forensic work.

Keywords: clay mineralogy, forensic soils analysis, sequential analyses, kaolinite, gibbsite

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Authors: Jasna M. Čanadanović-Brunet, Gordana S. Ćetković, Jelena J. Vulić, Sonja M. Djilas, Vesna T. Tumbas Šaponjac, Sladjana M. Stajčić

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Honey serves as a source of natural antioxidants, which are effective in reducing the risk of heart disease, cancer, immune-system decline, cataracts, different inflammatory processes, and also prevent deteriorative oxidation reactions in foods such as enzymatic browning of fruit and vegetables. Honey is a natural saturated sugar solution, but it also contains certain minor constituents, proteins, enzymes, amino and organic acids, lipids, vitamins, phenolic acids, flavonoids and carotenoids. It is consumed in its natural form alone, but also in combination with nuts and various kinds of dried fruits. The aim of this research was to investigate the contribution of dried cherry on phenols (TPh) and flavonoids (Fl) contents and antioxidant activities of honey. Phenolic compounds in Serbian polyfloral (PH), linden (LH) and acacia (AH) honey and also in their mixtures with dried cherry, in 40% mass concentrations (PH40; LH40, AH40), were determined. In comparison to honey, TPh increased 2.25 times for LH40, 2.16 times for AH40 and 1.45 times for PH40, while Fl increased 2.81-fold for PH40, 1.21-fold for LH40 and 1.44-fold for AH40. Antioxidant activity was investigated with two assays, DPPH test and reducing power (RP), and expressed as EC50DPPH and RP0.5 values. The EC50DPPH values were: EC50PH40 = 1.16 mg/ml; EC50LH40= 1.42 mg/ml and EC50AH40= 1.69 mg/ml, while RP0.5 were: RP0.5PH40 = 15.05 mg/ml; RP0.5LH40 = 16.09 mg/ml and P0.5AH40 = 17.60 mg/ml. Our results indicate that supplementation of polyfloral, linden and acacia honey with 40% dried cherry improves antioxidant activity of honey by enriching the phenolic composition.

Keywords: antioxidant activity, dried cherry, honey, phenolics

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Authors: L. Bouqbis, H.W. Koyro, M. C. Harrouni, S. Daoud, L. F. Z. Ainlhout, C. I. Kammann

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The application of biochar to soils is becoming more and more common. Its application which is generally reported to improve the physical, chemical, and biological properties of soils, has an indirect effect on soil health and increased crop yields. However, many of the previous results are highly variable and dependent mainly on the initial soil properties, biochar characteristics, and production conditions. In this study, two biochars which are biochar II (BC II) derived from a blend of paper sludge and wheat husks and biochar 005 (BC 005) derived from sewage sludge with a KCl additive, are used, and the physical and chemical properties of BC II are characterized. To determine the potential impact of salt stress and toxic and volatile substances, the second part of this study focused on the effect biochars have on germination of salad (Lactuca sativa L.), barley (Hordeum vulgare), and cress (Lepidium sativum) respectively. Our results indicate that Biochar II showed some unique properties compared to the soil, such as high EC, high content of K, Na, Mg, and low content of heavy metals. Concerning salad and barley germination test, no negative effect of BC II and BC 005 was observed. However, a negative effect of BC 005 at 8% level was revealed. The test of the effect of volatile substances on germination of cress revealed a positive effect of BC II, while a negative effect was observed for BC 005. Moreover, the water holding capacities of biochar-sand mixtures increased with increasing biochar application. Collectively, BC II could be safely used for agriculture and could provide the potential for a better plant growth.

Keywords: biochar, phytotoxic tests, seedlings growth, water holding capacity

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Authors: T. Nozu, K. Hibi, T. Nishiie

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This paper discusses the applicability of the numerical model for a damage prediction method of the accidental hydrogen explosion occurring in a hydrogen facility. The numerical model was based on an unstructured finite volume method (FVM) code “NuFD/FrontFlowRed”. For simulating unsteady turbulent combustion of leaked hydrogen gas, a combination of Large Eddy Simulation (LES) and a combustion model were used. The combustion model was based on a two scalar flamelet approach, where a G-equation model and a conserved scalar model expressed a propagation of premixed flame surface and a diffusion combustion process, respectively. For validation of this numerical model, we have simulated the previous two types of hydrogen explosion tests. One is open-space explosion test, and the source was a prismatic 5.27 m3 volume with 30% of hydrogen-air mixture. A reinforced concrete wall was set 4 m away from the front surface of the source. The source was ignited at the bottom center by a spark. The other is vented enclosure explosion test, and the chamber was 4.6 m × 4.6 m × 3.0 m with a vent opening on one side. Vent area of 5.4 m2 was used. Test was performed with ignition at the center of the wall opposite the vent. Hydrogen-air mixtures with hydrogen concentrations close to 18% vol. were used in the tests. The results from the numerical simulations are compared with the previous experimental data for the accuracy of the numerical model, and we have verified that the simulated overpressures and flame time-of-arrival data were in good agreement with the results of the previous two explosion tests.

Keywords: deflagration, large eddy simulation, turbulent combustion, vented enclosure

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Authors: Samiya Siddique, Taslima Akter Elma, Shahrina Mahzabin, Tamanna Jerin, Mohammed Russedul Islam

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In the maneuver and designing of highway engineering, pavement performance is a principal concern. Quality of construction and materials, traffic volume, climate, etc. are the factors that affect the performance of asphalt concrete. Modified asphalt requires to attain greater strength and stability even at inimical circumstances. In this point of view, pyrolytic carbon black (PCB), which is a by-product of waste tire pyrolysis, holds incomparable properties that individualizes it from other conventional fillers by making it an imminent modifier of bitumen. Optimum asphalt content of 60/70 penetration grade asphalt is determined 5% through the Marshall Stability and Flow test for the wearing course of flexible pavement. 5, 10, and 15 percentages of PCB are then used with neat asphalt for modification. Deviations of physical and rheological properties are investigated on both PCB modified and neat asphalt by going through several laboratory tests such as penetration, softening point, and ductility tests. The obtained results reveal that the performance of paving asphalt can be upgraded by modifying it with PCB. With the increasing percentage of PCB, ductility is gradually decreased, and also penetration grade is gradually reduced from 60/70 to 30/40. Furthermore, asphalt mixtures modified with PCB demonstrate higher stability and lower flow values. The research discloses that the apposite percentage of PCB used in asphalt concrete plays a significant role in the advancement of pavement performances and reutilizing of waste tires.

Keywords: asphalt modification, pavement performances, pyrolytic carbon black, marshall stability, wearing course

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Authors: Ren Moses, Emmanuel Kidando, Eren Ozguven, Yassir Abdelrazig

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This study applied traffic speed and occupancy to develop clustering models that identify different traffic conditions. Particularly, these models are based on the Dirichlet Process Mixture of Generalized Linear regression (DML) and change-point regression (CR). The model frameworks were implemented using 2015 historical traffic data aggregated at a 15-minute interval from an Interstate 295 freeway in Jacksonville, Florida. Using the deviance information criterion (DIC) to identify the appropriate number of mixture components, three traffic states were identified as free-flow, transitional, and congested condition. Results of the DML revealed that traffic occupancy is statistically significant in influencing the reduction of traffic speed in each of the identified states. Influence on the free-flow and the congested state was estimated to be higher than the transitional flow condition in both evening and morning peak periods. Estimation of the critical speed threshold using CR revealed that 47 mph and 48 mph are speed thresholds for congested and transitional traffic condition during the morning peak hours and evening peak hours, respectively. Free-flow speed thresholds for morning and evening peak hours were estimated at 64 mph and 66 mph, respectively. The proposed approaches will facilitate accurate detection and prediction of traffic congestion for developing effective countermeasures.

Keywords: traffic congestion, multistate speed distribution, traffic occupancy, Dirichlet process mixtures of generalized linear model, Bayesian change-point detection

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Authors: Nabila Mohamed, Santiago Aparicio, Bahman Tohidi, Mert Atilhan

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Qatar's one of the biggest problem in processing its natural resource, which is natural gas, is the often occurring blockage in the pipelines caused due to uncontrolled gas hydrate formation in the pipelines. Several millions of dollars are being spent at the process site to dehydrate the blockage safely by using chemical inhibitors. We aim to establish national database, which addresses the physical conditions that promotes Qatari natural gas to form gas hydrates in the pipelines. Moreover, we aim to design and test novel hydrate inhibitors that are suitable for Qatari natural gas and its processing facilities. From these perspectives we are aiming to provide more effective and sustainable reservoir utilization and processing of Qatari natural gas. In this work, we present the initial findings of a QNRF funded project, which deals with the natural gas hydrate formation characteristics of Qatari type gas in both experimental (PVTx) and computational (molecular simulations) methods. We present the data from the two fully automated apparatus: a gas hydrate autoclave and a rocking cell. Hydrate equilibrium curves including growth/dissociation conditions for multi-component systems for several gas mixtures that represent Qatari type natural gas with and without the presence of well known kinetic and thermodynamic hydrate inhibitors. Ionic liquids were designed and used for testing their inhibition performance and their DFT and molecular modeling simulation results were also obtained and compared with the experimental results. Results showed significant performance of ionic liquids with up to 0.5 % in volume with up to 2 to 4 0C inhibition at high pressures.

Keywords: gas hydrates, natural gas, ionic liquids, inhibition, thermodynamic inhibitors, kinetic inhibitors

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Authors: M. Al Zallouha, Y. Landkocz, J. Brunet, R. Cousin, J. M. Halket, E. Genty, P. J. Martin, A. Verdin, D. Courcot, S. Siffert, P. Shirali, S. Billet

Abstract:

Toluene is one of the most used Volatile Organic Compounds (VOCs) in the industry. Amongst VOCs, Benzene, Toluene, Ethylbenzene and Xylenes (BTEX) emitted into the atmosphere have a major and direct impact on human health. It is, therefore, necessary to minimize emissions directly at source. Catalytic oxidation is an industrial technique which provides remediation efficiency in the treatment of these organic compounds. However, during operation, the catalysts can release some compounds, called byproducts, more toxic than the original VOCs. The catalytic oxidation of a gas stream containing 1000ppm of toluene on Pd/α-Al2O3 can release a few ppm of benzene, according to the operating temperature of the catalyst. The development of new catalysts must, therefore, include chemical and toxicological validation phases. In this project, A549 human lung cells were exposed in air/liquid interface (Vitrocell®) to gas mixtures derived from the oxidation of toluene with a catalyst of Pd/α-Al2O3. Both exposure concentrations (i.e. 10 and 100% of catalytic emission) resulted in increased gene expression of Xenobiotics Metabolising Enzymes (XME) (CYP2E1 CYP2S1, CYP1A1, CYP1B1, EPHX1, and NQO1). Some of these XMEs are known to be induced by polycyclic organic compounds conventionally not searched during the development of catalysts for VOCs degradation. The increase in gene expression suggests the presence of undetected compounds whose toxicity must be assessed before the adoption of new catalyst. This enhances the relevance of toxicological validation of such systems before scaling-up and marketing.

Keywords: BTEX toxicity, air/liquid interface cell exposure, Vitrocell®, catalytic oxidation

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Authors: Mohamed Saad Gad Elzoghby

Abstract:

Nanomaterials are widely used nowadays for the consolidation of degraded archaeological limestone. It’s one of the most predominant stones in monumental buildings and statuary works. It is exposed to different weathering processes that cause degradation and the presence of deterioration pattern as cracks, fissures, and granular disintegration. Nanomaterials have been applied to limestone consolidation. Among these nanomaterials are nanolimes, i.e., dispersions of lime nanoparticles in alcohols, and nano-silica, i.e., dispersions of silica nanoparticles in water, promising consolidating products for limestone. It was investigated and applied to overcome the disadvantages of traditional consolidation materials such as lime water, water glass, and paraliod. So, researchers investigated and tested the effectiveness of nanomaterials as consolidation materials for limestone. The present study includes an evaluation of some nanomaterials in consolidation limestone stone in comparison with traditional consolidants. These consolidation materials are nano calcium hydroxide nanolime, and nanosilica. The latter is known commercially as Nano Estel and the former Known as Nanorestore compared to traditional consolidants Wacker OH (ethyl silicate) and Paraloid B72 (a copolymer of ethyl methacrylate and methyl acrylate). The study evaluated the consolidation effectiveness of nanomaterials and traditional consolidants by using followed methods, characterization of physical properties of stone, scanning electron microscopy (SEM), X-ray diffractometry, Fourier transforms infrared spectroscopy, and mechanical properties. The study confirmed that nanomaterials were better in the distribution and encapsulation of calcite grains in limestone, and traditional materials were better in improving the physical properties of limestone. It demonstrated that good results could be achieved through mixtures of nanomaterials and traditional consolidants.

Keywords: nanomaterials, limestone, consolidation, evaluation, weathering, nanolime, nanosilica, scanning electron microscope

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Authors: Li-Xin Shi, Meng-Fei Hu, Song-Chuan Zhao

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Dense particle suspensions composed of mixtures of particles and fluid are omnipresent in natural phenomena and in industrial processes. Dense particle suspension under shear may lose its uniform state to large local density and stress fluctuations which challenge the mean-field description of the suspension system. However, it still remains largely debated and far from fully understood of the internal mechanism. Here, a dynamics of a non-Brownian suspension is explored under horizontal swirling excitations, where high-density patches appear when the excitation frequency is increased beyond a threshold. These density patches are self-assembled into a hexagonal pattern across the system with further increases in frequency. This phenomenon is underlined by the spontaneous growth of density waves (instabilities) along the flow direction, and the motion of these density waves preserves the circular path and the frequency of the oscillation. To investigate the origin of the phenomena, the constitutive relationship calibrated by independent rheological measurements is implemented into a simplified two-phase flow model. And the critical instability frequency in theory calculation matches the experimental measurements quantitatively without free parameters. By further analyzing the model, the instability is found to be closely related to the discontinuous shear thickening transition of the suspension. In addition, the long-standing density waves degenerate into random fluctuations when replacing the free surface with rigid confinement. It indicates that the shear-thickened state is intrinsically heterogeneous, and the boundary conditions are crucial for the development of local disturbance.

Keywords: dense suspension, instability, self-organization, density wave

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Authors: Aung Phyo Kyaw, Kuo Chieh Chao

Abstract:

Expansive soils are more complicated than normal soils, although the soil itself is not very complicated. When evaluating foundation performance on expansive soil, it is important to consider soil expansion. The primary focus of this study is on hydraulic cement and expansive soil mixtures, and the research aims to identify key parameters for controlling the swell of the expansive soil-hydraulic cement mixture. Treatment depths can be determined using hydraulic cement ratios of 4%, 8%, 12%, and 15% for treating expansive soil. To understand the effect of hydraulic cement percentages on the swelling of expansive soil-hydraulic admixture, performing the consolidation-swell test σ''ᶜˢ is crucial. This investigation primarily focuses on consolidation-swell tests σ''ᶜˢ, although the heave index Cₕ is also needed to determine total heave. The heave index can be measured using the percent swell in the specific inundation stress in both the consolidation-swell test and the constant-volume test swelling pressure. Obtaining the relationship between swelling pressure and σ''ᶜⱽ determined from the "constant volume test" is useful in predicting heave from a single oedometer test. The relationship between σ''ᶜˢ and σ''ᶜⱽ is based on experimental results of expansive soil behavior and facilitates heave prediction for each soil. In this method, the soil property "m" is used as a parameter, and common soil property tests include compaction, particle size distribution, and the Atterberg limit. The Electricity Generating Authority of Thailand (EGAT) provided the soil sample for this study, and all laboratory testing is performed according to American Society for Testing and Materials (ASTM) standards.

Keywords: expansive soil, swelling pressure, total heave, treatment depth

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Authors: A. S. Akinbani

Abstract:

Overdependence on petroleum is causing set back in Nigeria economy. Field survey was carried out to assess the profitability and production of selected arable crops in six selected towns and villages of Ondo southwestern. Data were collected from 240 arable crop farmers with the aid of both primary and secondary data. Data were collected with the use of oral interview and structured questionnaires. Data collected were analyzed using both descriptive and inferential statistics. Forty farmers were randomly selected to give a total number of 240 respondents. 84 farmers interviewed had no formal education, 72 had primary education, 50 farmers attained secondary education while 38 attained beyond secondary education. The majority of the farmers hold less than 10 acres of land. The data collected from the field showed that 192 farmers practiced mixed cropping which includes mixtures of yam, cowpea, cocoyam, vegetable, cassava and maize while only 48 farmers practiced monocropping. Among the sampled farmers, 93% agreed that arable production is profitable while 7% disagreed. The findings show that managerial practices that conserve the soil fertility and reduce labor cost such as planting of leguminous crops and herbicide application instead of using hand held hoe for weeding should be encouraged. All the respondents agreed that yam, cowpea, cocoyam, sweet potato, rice, maize and vegetable production will solve the problem of hunger and increase standard of living compared with petroleum product that Nigeria relied on as means of livelihood.

Keywords: farmers, arable crop, cocoyam, respondents, maize

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Authors: Pixiang Wang, Shaoyang Liu, Yucheng Peng

Abstract:

Polypropylene (PP) is an essential material of numerous applications in different industrial sectors, including packaging, construction, and automotive. Because the application of homopolypropylene (HPP) is limited by its relatively low impact strength and high embrittlement temperature, various types of impact copolymer PP (ICPP) that incorporate elastomers/rubbers into HPP to increase impact strength have been successfully commercialized. Crystallization kinetics of an isotactic HPP, an ICPP, and their composites were studied in this work understand the composites’ behaviors better. The Avrami-Jeziorny model was used to describe the crystallization process. For most samples, the Avrami exponent, n, was greater than 3, indicating the crystal grew in three dimensions with spherical geometry. However, the n value could drop below 3 when the ICPP content was 80 wt.% or higher and the cooling rate was 7.5°C/min or lower, implying that the crystals could grow in two dimensions and some lamella structures could be formed under those conditions. The nucleation activity increased with the increase of the ICPP content, demonstrating that the rubber phase in the ICPP acted as a nucleation agent and facilitated the nucleation process. The decrease in crystallization rate after the ICPP content exceeded 60 wt.% might be caused by the excessive amount of crystal nuclei induced by the high ICPP content, which caused strong crystal-crystal interactions and limited the crystal growth space. The nucleation activity and the n value showed high correlations to the mechanical and thermal properties of the materials. The quantitative study of the kinetics of crystallization in this work could be a helpful reference for manufacturing ICPP and HPP/ICPP mixtures.

Keywords: polypropylene, crystallization kinetics, Avrami-Jeziorny model, crystallization activation energy, Nucleation activity

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