Papers by Keyword: Synergistic Effect

Abstract: Mild steel material has broad application in marine construction, due to their availability, low cost, and high tensile strength. Nevertheless, the major limitation of mild steel is its low corrosion resistance. The use of eco-friendly inhibitors in protecting mild steel from aggressive media is one of the cheap and practical means competing with conventional phosphate and chromate inhibitors. Herein, the synergism corrosion inhibition effects between key lime and chlorpheniramine drug were examined as sustainable inhibitors for mild steel in 24.5 M NaCl solutions through electrochemical measurement, and morphology of the same was characterized using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDX). The electrochemical investigations revealed that in the presence of 2ml key lime and 8ml chlorpheniramine drug the optimum inhibitive efficiency of 81.82% was achieved, this is connected to the protecting layer build-up on the surface of the mild steel, thus, blocking the harsh ion diffusion pathway. The polarization plot shows that the inhibitors complex the deposition led to the corrosion inhibition mixed-type mechanisms. The films formed on the mild steel surface were proved by the SEM/EDX result. The adsorption result shows that the inhibitors fit the Langmuir adsorption isotherm. Keywords: Synergistic effect, sustainable corrosion inhibition, NaCl solution, electrochemical techniques, mild steel

Abstract: Cinnamon bark oil (CO) has anticancer activity in various type of cancer cells and could be used alternatively to support anticancer drugs. For the enhancement of cytotoxic effects, the combination of bioactive compounds with chemotherapeutics drug has been interested in the possibility of cancer treatment. This study aimed to determine whether there is a synergistic effect between the combination of CO and chemotherapeutic drug such as imatinib mesylate (IM) on HCT 116 and HT29 colorectal cancer cell lines. The cytotoxic activities of CO and IM were investigated individually and their combination in each cancer cell line using cell viability assay. The interaction between CO and IM was determined using the combination index (CI) method. Cinnamon bark oil exhibited the high cytotoxicity on HCT116 cell, while IM showed the high cytotoxic activity on HT 29 cell. The tested combination decreased notably viability of cell and allowed to reduce the dose of imatinib chemotherapy drug. The combination of CO with IM showed a strong synergistic effect (CI < 1) on HT29 cell. For HCT116 cell treated combination of CO (4μg/mL) and IM (10μg/mL) demonstrated a strong synergistic effect (CI = 0.52). Thus, the combined CO and IM might be applied for pharmaceutical drug delivery for colon cancer treatment.

Abstract: The use of calcined clay and limestone as supplementary cementitious materials, can have a certain influence on the hydration of Portland cement. This paper reviewed the influence of limestone and calcined clay and the mixture of limestone and calcined clay on the hydration of cement. Both limestone and calcined clay accelerate the hydration reaction in the early hydration age and enhance the properties of cement. Limestone reacts with C₃A to form carboaluminate, which indirectly stabilized the presence of ettringite, while calcined clay consumed portlandite to form C-(A)-S-H gel, additional hydration products promote the densification of pore structure and increase the mechanical properties. The synergistic effect of calcined clay and limestone stabilize the existence of ettringite and stimulate the further formation of carboaluminate, as well as the C-(A)-S-H gel, contributed to a dense microstructure.

Abstract: Hydrophilic amino acids as a new type hydrate inhibitor is a hot topic for scholars. In this paper, the influence of glycine and L-arginine, and their complexation with polyvinylpyrrolidone (PVP) on hydrate formation were clarified by tetrahydrofuran (THF) hydrate formation simulation experiments, and the intrinsic influence mechanism was revealed by many experimental methods. The results show that glycine has a strong inhibitory effect on water molecules because of its strong disturbance to water molecules, and the inhibitory effect is the best when the addition of glycine is 1.0 wt%. Due to the disturbance and binding of hydrophilic amino acids to water molecules, the effect of PVP on the semi-cage structure of water molecules as well as the adsorption and encapsulation of hydrate crystal particles, the combination of glycine and L-arginine and PVP has synergistic inhibitory effect on the formation of THF hydrate. When the total amount of hydrate inhibitor is 1.0 wt%, the synergistic inhibition ability of glycine and PVP is stronger. The results obtained in this paper provide an experimental and theoretical basis for the research and development of new hydrate inhibitors.

Abstract: This study examined the co-pyrolysis characteristics of low-rank coal (SJC) and direct coal liquefaction residue (DCLR) through thermogravimetric analysis coupled with Fourier transform infrared spectrometry. It also investigated the influences of different mass fractions of DCLR to SJC on the co-pyrolysis characteristics and release regulation of gas phase components. Results showed that with increasing DCLR content, coke yield initially decreased and then increased, but tar and gas yield reversed. Different addition of DCLR changed the composition of the pyrolysis gas in various degrees, and reduced the content of-OH and nitrogen compounds in coke. The H₂ content in the gas gradually increased. When 40% DCLR was added, the maximum tar yield was 22.79%, and the maximum H₂ yield was 37.12%. At 60% DCLR, the lowest semi-coke yield was 65.01%, and the highest gas yield was 14.65%. The co-pyrolysis of SJC and DCLR can be divided into three stages. The first was the dry degassing stage, during which the adsorbed gas and small-molecule gas were removed on the coal surface at room temperature to 350 °C. The second stage (350 °C–650 °C) was the intense pyrolysis reaction stage, during which a large number of volatiles were obtained. The substantial weight loss rate peak appeared around 450 °C. The weight loss rate of pyrolysis gradually increased with increasing DCLR dosage. The co-pyrolysis of SJC and DCLR was not a simple sum between SJC and DCLR, which indicated a synergistic effect in the co-pyrolysis. The synergistic effect between SJC and DCLR enhances the interaction between free-radical fragments, thereby increasing the yield of pyrolysis tar. The third stage was the shrinkage of semi-coke from 650 °C to the end of the reaction. The polycondensation reaction between free-radical fragments to form solid coke with higher aromaticity, and H₂ released.

Abstract: The non-oxygenated fraction of bio-oil is precursor of the formation of biofuel because it contains hydrocarbon only. Zeolite catalysts have been proved to improve the yields of non-polar fraction of bio-oil in case of fast co-pyrolysis. In the present work, the catalysts were applied to slow co-pyrolysis to investigate their effect on the yields and compositions of non-oxygenated fractions of bio-oil. The co-pyrolysis was conducted in a stirred tank reactor using non catalyst (thermal co-pyrolysis), natural zeolite and H-beta zeolite catalysts with heating rate of 5°C/minute from ambient temperature to 500°C and PP composition in combined feed varied 0, 50, and 100% weight of PP. As biomass, the present study used corn cobs. The results show that synergistic effect on the yield of non-oxygenated fraction in co-pyrolysis involving natural zeolite was lower than that in thermal co-pyrolysis and co-pyrolysis involving H-beta-zeolite exhibited negative synergistic effect. H-NMR analysis of the fraction from co-pyrolysis involving 50% weight of PP shows that the bio-oil contained approximately methyl H of about 55% by mol, methine H of 20% and methylene H of about 15% irrespective of catalysts used. This composition was closer to that of commercial gasoline rather than commercial diesel compositions.

Abstract: This study aims to investigate the interaction during the co-pyrolysis of Cangzhou coal and sawdust/rice husk. The synergistic is analyzed in the thermal behavior of the blends and the kinetics by thermogravimetric analysis (TG), also in the products yield (oil and char) from the fast co-pyrolysis and the oil characterization by GC-MS and UV fluorescence spectroscopy. Firstly TG experiment indicated the synergistic effect occurs during the co-pyrolysis process of the coal and rice husk occurs during the all the main pyrolysis (300-550°C) and that of the sawdust between 300-410°C (for the 50:50 and the 75:25 blends) and 300-550°C (for the 25:75 blend). Then the co-fast pyrolysis in a novel auger reactor increased the oil yield compared to the predicted values. The synergistic interaction promoted the oxygenated compounds, limited the SO_x emissions, was less reactive and did not promote the aromatic components.

Abstract: Three curcumin analogs of dimethylaminobenzaldehyde derivatives, i.e., A, B and C were synthesized using a green method using the ultrasound-assisted technique, and the process was compared to the conventional method. The improvements were achieved by decreasing the reaction time from hours to minutes and giving the higher yields of the products. The products were tested as an antidiabetic agent by treated them as an inhibitor for α-amylase activity. The result of α-amylase inhibition showed that curcumin analogs (A, B, C) have high inhibition (77.06; 76.59; 78.34%) with IC₅₀value 23.64; 1.36; and 5.93 μg/mL, respectively. Meanwhile, the α-amylase inhibition of the combination between curcumin analog and ferulic acid showed that the curcumin analog C gave the highest inhibition level of 95.94% with IC₅₀ 13.38 μg/mL. The combination of curcumin analog A and ferulic acid has a strong synergistic effect with a combination index (CI) value of less than 1, i.e., 0.33. These curcumin analogs are quite potent in inhibiting the activity of α-amylase so that it can be a good candidate for antidiabetic drugs.

Abstract: The synergistic effect associated with displacement damage, hydrogen and heliumin the China Low Activation Martensitic (CLAM) steel has been investigated using the triple ion beamirradiation. Triple ion beams, an iron beam of 109 MeV degraded by a tantalum foil of 7.45 μm thick, the100 keV hydrogen and 200 keV helium, were injected into the CLAM steel samples simultaneously or sequentially.The radiation damage examinations were carried out by the slow positron Doppler broadening technique. Themeasured S parameters indicate that the radiation damage is different for different irradiationprocedures with same dpa and concentrations of H and He. The sample suffers most severe damage in the simultaneoustriple beam irradiation. The present experimental results support the molecular dynamics simulation result that the H facilitates the He-bubble nucleation and growth.

Abstract: Lignocellulosic biomass can nowadays be bioconverted to value-added biofuels by numerous cellulases purified from diverse microbes. In nature, complex microbial communities produce multifunctional cellulase systems with broader substrate utilization and act sequentially in the synergistic action by subsequently converting cellulose into an utilizable energy source and glucose. This research was to apply cellulase producing isolates based on their possible synergistic action to degrade complex cellulose containing biomass. In the study, the microorganism species, isolated species from durian peels after macerated for 3 days and shown for their high biodegradation activity, Bacillus spp. (B12, B13, and B16) and Pseudomonas spp., (B23 and B55), could express high cellulase activity on carboxymethylcellulose (CMC) and filter paper (FP). Bacillus spp. B13 and B16 showed high cellulase activity on soluble cellulose of CMC while B12 and B55 displayed high cellulase activity on crystalline insoluble cellulose of FP. To observe the synergistic effect of the cellulase-producing consortia, co-cultures of B12,B23 and F23 were grew well on both CMC and FP. Therefore, these findings of synergistic effects of microbial consortia could bring us a future work to develop high efficient cellulase producing systems for further industry application.