Miracle-dz/UniFAR-FTUs huggingface dataset:
Comparative study of boron compounds and aluminum trihydroxide as flame retardant additives in epoxy resin

The aim of this study was to investigate and compare the flame retardant properties of boron compounds with respect to aluminum trihydroxide (ATH) in an epoxy system based on bisphenol A epichlorohydrin-based epoxy resin and cycloaliphatic polyamine-based hardener. Six different boron compounds including colemanite (C), ulexite (U), boric acid (BA), boric oxide (BO), melamine borate (MB) and guanidinium nonaborate (GB) were used as flame retardant additive. The flame retardant properties of epoxy-based composites were investigated using limiting oxygen index (LOI), UL 94 standards both in vertical and horizontal position, thermogravimetric analysis, cone calorimeter and scanning electron microscopy. According to flammability test results, boron compounds except for C and U showed better performance than ATH. According to the LOI results, 40% BA containing sample had the highest LOI value of 28.5, while 30% MB, 35% GB and 40% BA containing samples had the highest UL 94V rating (V0). According to the cone calorimeter test results, all boron containing samples had better fire performances than ATH containing sample; 40 wt% BO containing sample showed the lowest peak heat release rate, average heat release rate and total heat release values. Copyright © 2014 John Wiley & Sons, Ltd.
Physicochemical characterization of α-chitin, β-chitin, and γ-chitin separated from natural resources

We isolated α-chitin, β-chitin, and γ-chitin from natural resources by a chemical method to investigate the crystalline structure of chitin. Its characteristics were identified with Fourier transform infrared (FTIR) and solid-state cross-polarization/magic-angle-spinning (CP–MAS) 13C NMR spectrophotometers. The average molecular weights of α-chitin, β-chitin, and γ-chitin, calculated with the relative viscosity, were about 701, 612, and 524 kDa, respectively. In the FTIR spectra, α-chitin, β-chitin, and γ-chitin showed a doublet, a singlet, and a semidoublet at the amide I band, respectively. The solid-state CP–MAS 13C NMR spectra revealed that α-chitin was sharply resolved around 73 and 75 ppm and that β-chitin had a singlet around 74 ppm. For γ-chitin, two signals appeared around 73 and 75 ppm. From the X-ray diffraction results, α-chitin was observed to have four crystalline reflections at 9.6, 19.6, 21.1, and 23.7 by the crystalline structure. Also, β-chitin was observed to have two crystalline reflections at 9.1 and 20.3 by the crystalline structure. γ-Chitin, having an antiparallel and parallel structure, was similar in its X-ray diffraction patterns to α-chitin. The exothermic peaks of α-chitin, β-chitin, and γ-chitin appeared at 330, 230, and 310, respectively. The thermal decomposition activation energies of α-chitin, β-chitin, and γ-chitin, calculated by thermogravimetric analysis, were 60.56, 58.16, and 59.26 kJ mol−1, respectively. With the Arrhenius law, ln β was plotted against the reciprocal of the maximum decomposition temperature as a straight line; there was a large slope for large activation energies and a small slope for small activation energies. α-Chitin with high activation energies was very temperature-sensitive; β-Chitin with low activation energies was relatively temperature-insensitive. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3423–3432, 2004
Flowering parameters of carnation (Dianthus caryophyllus L.) varieties under protected condition influenced by NPK nutrients through foliar spray

Studies were conducted on the flowering parameters of carnation (Dianthus caryophyllus L.) varieties under protected condition influenced by NPK nutrients through foliar spray. The experiment consisted of three varieties with five levels of fertilizers and it was laid out in Factorial Completely Randomized Design (FCRD) with three replications. The results of present investigation on flowering parameters revealed that variety Don Pedro Rapido with nutrient level 6000 N: 4000 P2O5: 2000 K2O ppm recorded significantly maximum harvesting span of flowers, fresh and dry weight of single cut flower, number of petals per flower, minimum days taken to flower bud initiation and minimum days taken to open of first flower.
The effect of molecular vibrations and surface structure on the chemisorption of methane on platinum

In this thesis, I report state-resolved measurements of the chemisorption probability of CH4 on Pt(111) and Pt(110)-(1×2) for several rovibrationally excited states (2ν3, ν1+ν4, and 2ν2+ν4) in addition to the ground state. Measurements of the state resolved reactivity as function of the incident translational energy lead to state-resolved reactivity curves for each of the states under study. The relative efficacy of activating the dissociation reaction is obtained for each excited state by comparing the increase in reactivity observed upon excitation of a particular state to the effect of increasing the translational energy of CH4 in the ground state. The results provide clear evidence for mode specific reactivity with the highest efficacy for the stretch-bend combination (ν1+ν4), followed by the stretch overtone (2ν3) and the bend overtone state (2ν2+ν4). The results demonstrate that vibrational activation of CH4/Pt chemisorption process does not simply scale with the total internal energy of the incident CH4 molecule, which is a central assumption of the PC-MURT statistical model for dissociative chemisorption reactions developed by the group of Harrison [Ukraintsev et al., Chem. Phys., 1994. 101(2): p. 1564]. On the contrary, the qualitative predictions of the vibrationally adiabatic model proposed by Halonen et al. [J. Chem. Phys., 2001. 115(12): p. 5611] are in good agreement with our results. The higher efficacy of the ν1+ν4 state can also be rationalized by observing that, at the transition state, the breaking C-H bond is both stretched and bent from its equilibrium geometry, therefore I suggest that this state might have a significant projection on the reaction coordinate [Psofogiannakis et al., J. Phys. Chem. B, 2006. 110 : p. 24593 ; Anghel et al., Phys. Rev. B, 2005. 71 : p. 4]. Comparison between the state-resolved reactivity for CH4(2ν3) on Pt(111) and Ni(111) is used to obtain information about differences in barrier height and transition state location for the dissociation on the two different metals [Bisson et al., J. Phys. Chem., 2007. 111: p. 12679]. Finally, for the more corrugated Pt(110)-(1×2) surface, I determined the state-resolved sticking coefficients for different polar and azimuthal angles of incidence. Comparison between the reaction probability for incidence parallel and perpendicular to the missing rows of this surface shows shadowing effects that are consistent with predominant reactivity of the top layer Pt atoms.
Pyrolysis of Large Black Liquor Droplets

This paper presents the results of experiments involving the pyrolysis of large black liquor droplets in the NASA KC-135 reduced gravity aircraft. The reduced gravity environment facilitated the study of droplets up to 9 mm in diameter extending the results of previous studies to droplet sizes that are similar to those encountered in recovery boilers. Single black liquor droplets were rapidly inserted into a 923 K oven. The primary independent variables were the initial droplet diameter (0.5 mm to 9 mm), the black liquor solids content (66.12% - 72.9% by mass), and the ambient oxygen mole fraction (0.0 - 0.21). Video records of the experiments provided size and shape of the droplets as a function of time. The results show that the particle diameter at the end of the drying stage (D(sub DRY) ) increases linearly with the initial particle diameter (D(sub O)). The results further show that the ratio of the maximum swollen diameter (D(sub MAX)) to D(sub O) decreases with increasing D(sub O) for droplets with D(sub O) less than 4 mm. This ratio was independent of D(sub O) for droplets with D(sub O) greater than 4 mm. The particle is most spherical at the end of drying, and least spherical at maximum swollen size, regardless of initial sphericity and droplet size.
Disinfection Kinetics of Virus Aggregates of Bacteriophage MS2

The aim of this study was to determine the difference in disinfection between aggregated and dispersed virus. Bacteriophage MS2 was chosen as a surrogate for enteric virus. The first part of this project consisted of characterizing the aggregation of MS2 and the second part examined differences in the disinfection of aggregated and dispersed virus solutions. It was shown that MS2 only aggregated at a pH below its isoelectric point when the solution ionic strength was below 50 mM. At neutral pH, high ionic strength and CaCl2 did not cause aggregation. High ionic strength showed inhibition of aggregation at low pH. Aggregation was also influenced by the choice of buffer. The effect of the solution chemistry on the extent of aggregation at pH 3 was the following: acetic acid (20 mM)>sodium chloride (20 mM)> phosphate buffer (5 mM PO42-, 10 mM NaCl). Disinfection of the virus was thus tested at a pH above and under the isoelectric point at low ionic strength (phosphate buffer and 20 mM NaCl) in order to have dispersed and aggregated MS2 virus, respectively. Ultraviolet light (UV) and peracetic acid (PAA) were the chosen disinfection techniques as they are generally regarded as pH independent. UV showed greater disinfection capacity for the aggregated system than for the mono- dispersed system. Both disinfection curves showed first order kinetics. This observed difference in disinfection rates may not be due to the aggregation state of the virus but to other mechanisms, including the effect of pH on direct and indirect oxidation (by ROS) of amino acids in the virus capsid proteins. This is supported by the fact that UV can penetrate within the virus unlike a chemical disinfectant which must be in physical contact with a virus component for a reaction to take place. In order to test the effect of direct contact by chemical disinfectants, an aggregated and a dispersed solution were spiked with PAA. A difference in the behavior of the disinfection curves in phosphate buffer was observed after an inactivation of 6 logs. The disinfection rate of the aggregated system slowed down (tailing) after some initial amount of disinfection, while the dispersed system was completely disinfected with one disinfection rate. This implies a solution with some large aggregates and many single viruses in the solution. In 20 mM NaCl the disinfection rate of the aggregated virus was much slower than for the dispersed system (kaggregated= 0.0224; kdispersed= 0.0747). Both inactivation curves showed first order kinetics. By applying Grant’s model (1995) an aggregation factor was calculated (b= 1.413). This indicates a very aggregated state with large aggregates.
Study of the Uptake of N2O5 by Water and NaCl Solutions

Using the droplet train technique, the uptake of N{sub 2}O{sub 5} by NaCl solution and pure water was studied as a function of temperature in the 262-278 K range. The N{sub 2}O{sub 5} uptake coefficients on pure water decrease from 0.03 to 0.013 with increasing temperature. With the NaCl solution, there was a lower nitrate yield, indicating that nitrogen compounds are formed after the N{sub 2}O{sub 5} uptake by reactions with NaCl. The NaCl uptake coefficient is greater than pure water, so N{sub 2}O{sub 5} may be reaction-controlled. 38 refs., 7 figs., 1 tab.
CO-CULTURE OF ACTIVATED MONOCYTES AND BREAST CARCINOMA CELLS INCREASE COLLAGEN DEGRADATION IN THREE DIMENSIONAL TISSUE CULTURE MODELS -

It is well established that interaction between macrophages and breast carcinoma cells plays an important role in carcinogenesis. However, the precise role of proteases in this process has not yet been clearly elucidated. Thus, the aims of the present study were to determine whether interaction between breast carcinoma cell lines MDA-MB-231 and human monocyte cell line U937 may modulate expression of proteases responsible for extracellular matrix degradation, as well as to identify the major proteases secreted by monocytes/macrophages and breast carcinoma cells. We used secretions of MDA-MB-231 to activate and differentiate U937 into active monocytes/macrophages. Activated U937 were seeded in co-culture with MDA-MB-231 on three dimensional in-vitro tissue culture models that recapitulate tumor microenvironment. Live cell imaging proteolysis assay was used to determine the proteolytic activity and degradation of collagen by co-culture spheroid. Then transwell co-culture plates were used to identify major proteases expressed due to interaction between U937 cells and MDA-MB-231 cells. Imaging assay results demonstrated that co-culture of activated U937 and MDA-MB-231 induced proteolytic activity of the co-culture spheroid one fold more than that induced in co-culture of control U937 and MDA-MB-231. The increase in proteolytic activity of co-culture spheroid was due to the interaction between breast carcinoma cells and monocytes, which resulted in the increase in expression and activity of intracellular proteases by U937, as well as increase in expression and secretion of pericellular proteases by MDA-MB-231. Transwell co-culture assay results showed that interaction between U937 and MDA-MB-231 induced 1) expression and activity of intracellular cathepsin B (CTSB) in U937; 2) expression and activity of secreted gelatinases [matrix metalloproteinase-2 and – 9 (MMP-2 and -9)] in MDA-MB-231 cells. In conclusion, paracrine interaction between breast carcinoma cells and activated monocytes/macrophages enhanced a proteolytic activity of the tumor microenvironment and degradation of the extracellular matrix proteins, which facilitates cancer growth and invasion.
Electrocatalytic Activity of Transition Metal Oxide-Carbon Composites for Oxygen Reduction in Alkaline Batteries and Fuel Cells

Conductive transition metal oxides (perovskites, spinels and pyrochlores) are attractive as catalysts for the air electrode in alkaline rechargeable metal-air batteries and fuel cells. We have found that conductive carbon materials when added to transition metal oxides such as calcium-doped lanthanum cobalt oxide, nickel cobalt oxide and calcium-doped lanthanum manganese cobalt oxide increase the electrocatalytic activity of the oxide for oxygen reduction by a factor of five to ten. We have studied rotating ring-disk electrodes coated with (a) various mass ratios of carbon and transition metal oxide, (b) different types of carbon additives and (c) different types of transition metal oxides. Our experiments and analysis establish that in such composite catalysts, carbon is the primary electro- catalyst for the two-electron electro-reduction of oxygen to hydroperoxide while the transition metal oxide decomposes the hydroperoxide to generate additional oxygen that enhances the observed current resulting in an apparent four-electron process. These findings are significant in that they change the way we interpret previous reports in the scientific literature on the electrocatalytic activity of various transition metal oxide- carbon composites for oxygen reduction, especially where carbon is assumed to be an additive that just enhances the electronic conductivity of the oxide catalyst. (C)more » 2013 The Electrochemical Society. All rights reserved. « less
Glycolysis Of Poly (Ethylene Terephthalate) (PET) Waste Under Conventional Convection-Conductive Glycolysis

Polyethylene terephthalate (PET) bottle wastes from disposable soft drink bottle were subjected to the depolymerization via glycolysis using excess of ethylene glycol. The reaction was carried out under conventional convection-conductive glycolysis in the presence of different class of metal catalyst as catalysts namely zinc acetate, sodium bicarbonate, zinc chloride and titanium (IV) oxide. The effect selection of catalyst and catalyst concentration (ratio catalyst:PET w/w%) on glycolysis depolymerization were investigated. After repeated crystallization, the glycolysis products were obtained with high conversion of 88%. It was subjected to the characterization by HPLC, TGA, DSC and FTIR analysis. It was found the glycolysis products consist mainly of bis 2-hydroxyethyl terephthalate (BHET) monomer with 75% recovery
Effect of cross‐linked polycarboxylate‐type superplasticizers on the properties in cementitious system

Fluidity and slump loss are main technical indicators for the quality of concrete. They are related to the dispersion of cement and hydration process, and are greatly affected by the structure of superplasticizers (SPs). For the purpose of obtaining SPs with excellent fluidity and slump retention, water-soluble cross-linked polycarboxylate ether copolymers (CLPCs) of acrylic acid and alkenyl alcohol type polyoxyethylene ether were synthesized. In order to gain full understanding of the effect of cross-linked SPs on the properties in cementitious system, properties of the new SPs in cement paste were compared to those of traditional ones without cross-linking agents. Mortar tests showed that CLPC performed obvious slow-release function and kept about 10 mm higher than its initial paste flow after 150 min, while PC incurred loss of 15 mm after 150 min. Adsorption of CLPC on cement resulted in zeta potential being roughly the same as that in the case of PC, and enabled more effective slump retention to cement suspensions by rheological property tests. Ettringite peaks disappeared for CLPC on 1-day curve and reappeared after 35 days, and the intensity of CH peaks for CLPC appeared weaker than Blank and PC after 1 day. The microstructure of CLPC after 1 day showed a very dense structure of smaller and thinner crystallites, which indicated that the early hydration was greatly delayed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40856.
MODELING USING A NEW THIN‐LAYER DRYING MODEL AND DRYING CHARACTERISTICS OF SWEET BASIL (OCIMUM BASLICUM LINN.) USING TRAY AND HEAT PUMP‐ASSISTED DEHUMIDIFIED DRYING

The maturity of Thai sweet basil was based on leaf area, % inhibition and total phenolics. Desorption isotherms for sweet basil leaves were performed. It was found that the modified Henderson model showed the best fit to both fresh and blanched sweet basil leaves for Xe = f(Xe,T). Sweet basil leaves were pretreated by blanching prior to drying under three temperatures of 40, 50 and 60C in tray and heat pump-dehumidified (HPD) dryers. The three-parameter model was the most effective model in describing sweet basil leaf drying. The drying constant was related to air temperature using the Arrhenius model. Effective moisture diffusivities increased with increasing temperature and blanching treatment, as well as the HPD dryer. Quality evaluation by % inhibition, total phenolics, rehydration ratio and ΔE* showed that the best quality resulted from sweet basil leaves pretreated by blanching and dried at 40C in HPD dryer. PRACTICAL APPLICATIONS Tray drying of sweet basil leaves is commonly performed in many industries. Up to now, the exporters have faced the problem of low total phenolics and antioxidant activity in dried sweet basil leaves. The new methods proposed in this study are blanching and heat pump-dehumidified (HPD) drying. The results revealed that blanching incorporated with HPD drying could reduce drying time and increase total phenolics, antioxidant activity and color values compared with the conventional tray drying. The three-parameter model proposed in this work was the most effective model to describe the mass transport behavior of dried sweet basil leaves.
Combustion of a Fuel Droplet in a Mixed Convective Environment

Abstract The combustion of a fuel droplet in a mixed convective environment has been simulated both theoretically and experimentally. In the theoretical model, the flow and transport equations have been solved subject to the assumptions of constant properties (except for density) and infinite rate kinetics, using the finite element method. The gas density has been treated as a variable, only to determine the buoyancy force contribution, and it has been evaluated assuming an ideal gas mixture. A porous-sphere facility has been employed for simulating the burning characteristics of a fuel droplet experimentally. The effects of airflow rate and droplet size have been studied for both upward and downward airflow configurations. Theoretical predictions for the mass burning rate and flame shape are in excellent agreement with the experimental results of the present study and also those reported in the literature. For upward airflow configuration, the mass burning rate is under-predicted by 15 to 20 percent when buoyancy effects are neglected. For downward airflow configuration, the flame shape is similar to the case of upward airflow for low air velocities. For higher downward air velocities, a flattened cylindrical flume front is obtained due to the opposing natural convection and forced convection flow fields, which has been predicted successfully. A detailed parametric study involving the variation of Reynolds number, ambient temperature and ambient oxygen concentration has also been carried out.
Improved alkalimetric monitoring for anaerobic digestion of high-strength wastes

Alkalinity measurements to pH endpoints of 5.75 and 4.3 were used to evaluate process stability of anaerobic digesters that treat a high-strength waste of various HRTs and feed concentrations. Total volatile acids concentrations, which varied between 500 mg/l as HAc during steady-state periods and nearly 10,000 mg/l as HAc during stress periods, correlated strongly with intermediate alkalinity (from pH 5.75 to 4.3). Partial alkalinity (to pH 5.75) was used to approximate bicarbonate concentration. Combination of both alkalinites into an IA: PA ratio greatly increased the sensitivity of the alkalinity test, and provided a simple, inexpensive parameter to detect process upset and recovery.
Magnetoelectric effect and low-temperature phase transitions of TbMn2O5

We made dielectric, magnetic and magnetoelectric measurements on single-crystal samples of TbMn2O5, which was an antiferromagnet with the Neel temperature of approximately 40 K. From the results, we concluded that there were two groups of phase transitions at lower temperatures. The first group are three successive transitions at 29.3, 27.2 and 25.6 K, whose natures are probably electric. The crystal is polar below this temperature range, because the polarity of the magnetoelectric effect can be controlled by electric field cooling. Another transition exists at 8 K, where time inversion symmetry breaks. It is related to the ordering of Tb3+ magnetic moments.