Number Of Moles Research Articles

Effect of Ammonia Addition on the Ignition Delay Mechanism of Methyl Decanoate

In this study, the effect of mixing a small amount of ammonia on the ignition delay time of methyl decanoate under different conditions was studied from the perspective of the combustion mechanism. The effect of adding ammonia on the ignition delay time of methyl decanoate at different pressures and temperatures was studied by means of simulation calculations and numerical comparison. Integrating the detailed mechanism and reaction path of methyl decanoate, the sensitivity of the ignition delay time was investigated. Analyses of the ignition delay time and rate of production were conducted to explore the transformation and influence of ammonia on the oxidation/decomposition process of the main elementary reaction during the ignition of methyl decanoate. The research illustrated that the ignition delay time of methyl decanoate increased with the number of moles of mixed ammonia at a certain temperature range, and in the negative temperature coefficient region, the effect of ammonia on the ignition delay time was the greatest. In addition, the susceptibility and yield analysis of methyl decanoate showed that the addition of ammonia had a weakening effect on the elementary reactions that originally promoted and inhibited methyl decanoate, and its consumption and production rates were reduced.

Removal of Mg and Ca from Ni-rich sulphate solutions by solvent extraction using cationic and neutral extractants

Selective solvent extraction of Mg and Ca aiming to purify Ni-rich sulfate solutions ([Ni] = 88 g/L, [Mg] = 3.1 g/L, [Ca] = 0.5 g/L) was investigated using the Cyanex 923 + Cyanex 272, and D2EHPA extractive systems (A/O ratio = 1, T = 50 °C). Although Cyanex 923 rejected metals at pH 3–6, a synergistic selective separation of Mg (69%) over Ca (1.2%, βMg/Ca = 179.2) and Ni (5.7%, βMg/Ni = 37.2) was attained at pH 5 with 0.13 M Cyanex 923 + 0.64 M Cyanex 272. Ni crowded out Mg from the loaded organic phase and limited the operation at pH < 5.5. Antagonism on Mg extractions was observed at [Cyanex 923] ≥ 0.25 M + 0.64 M Cyanex 272. Ni was selectively stripped out over Mg, using a dilute 0.031–0.063 M H2SO4, while Mg was stripped out with 0.25 M H2SO4. By contrast, 0.15 M D2EHPA selectively extracted Ca (50.8%) over Mg (2.1%, βCa/Mg = 47.6) and Ni (1.2%, βCa/Ni = 86.4) at pH 3, with Ca being crowded out by Ni at pH > 3. Selective Ni stripping was obtained from the loaded D2EHPA, using a dilute H2SO4 (0.034 M), while Ca and Mg were stripped by H2SO4 or HCl solutions (1 M). The real number of moles of extractants involved in the metal extractions and apparent equilibrium constants were determined for both extractive systems. Moreover, the FTIR spectra were accessed to contemplate the possible coordination compound structures.

Fabrication and Characterization of Nanostructured Rock Wool as a Novel Material for Efficient Water-Splitting Application.

Rock wool (RW) nanostructures of various sizes and morphologies were prepared using a combination of ball-mill and hydrothermal techniques, followed by an annealing process. Different tools were used to explore the morphologies, structures, chemical compositions and optical characteristics of the samples. The effect of initial particle size on the characteristics and photoelectrochemical performance of RW samples generated hydrothermally was investigated. As the starting particle size of ball-milled natural RW rises, the crystallite size of hydrothermally formed samples drops from 70.1 to 31.7 nm. Starting with larger ball-milled particle sizes, the nanoparticles consolidate and seamlessly combine to form a continuous surface with scattered spherical nanopores. Water splitting was used to generate photoelectrochemical hydrogen using the samples as photocatalysts. The number of hydrogen moles and conversion efficiencies were determined using amperometry and voltammetry experiments. When the monochromatic wavelength of light was increased from 307 to 460 nm for the manufactured RW>0.3 photocatalyst, the photocurrent density values decreased from 0.25 to 0.20 mA/mg. At 307 nm and +1 V, the value of the incoming photon-to-current efficiency was ~9.77%. Due to the stimulation of the H+ ion rate under the temperature impact, the Jph value increased by a factor of 5 when the temperature rose from 40 to 75 °C. As a result of this research, for the first time, a low-cost photoelectrochemical catalytic material is highlighted for effective hydrogen production from water splitting.

Synthesis of highly active solid base catalysts of SrO-ZrO2 and SrO-SiO2 by solid–liquid interface reactions of hydrated strontium hydroxide with metal alkoxides

Highly dispersed SrO in amorphous ZrO2 or SiO2, SrO–ZrO2, and SrO–SiO2 mixed oxides were synthesized by applying the solid–liquid interface reaction of Sr(OH)2•8 H2O in the solid phase with an equal number of moles of Zr(OC3H7)4 or with twice the number of Si(OC2H5)4 moles dissolved in 2-propanol. After heat treating at 723 K, the SrO–ZrO2 catalyst exhibited a higher activity than the conventional solid base MgO catalyst for the base-catalyzed retroaldol reaction of diacetone alcohol. The catalytic activity of SrO–ZrO2 was higher by a factor of 1.5 than that of MgO prepared by the thermal decomposition of hydrated magnesium oxalate (MgC2O4•2H2O). By contrast, the highest activity of SrO–SiO2 obtained by thermal activation at 673 K was much lower than that of MgO. The active SrO–ZrO2 catalyst was composed of catalytically inactive species of SrZrO3, and small amounts of Sr(OH)2 and SrCO3. The expected active species of SrO was not detected in powder X-ray diffraction analysis in any sample. The formation of SrO in small crystal size dispersed in amorphous ZrO2 was strongly expected. Similar results were obtained in the SrO–SiO2 sample. An active site formed on SrO–ZrO2 surface is proposed.

Conversion of Sewage Water into H2 Gas Fuel Using Hexagonal Nanosheets of the Polyaniline-Assisted Deposition of PbI2 as a Nanocomposite Photocathode with the Theoretical Qualitative Ab-Initio Calculation of the H2O Splitting.

This study is very promising for providing a renewable enrgy (H2 gas fuel) under the elctrochemical splitting of the wastwater (sewage water). This study has double benefits: hydrogen generation and contaminations removel. This study is carried out on sewage water, third stage treated, from Beni-Suef city, Egypt. Antimony tin oxide (ATO)/polyaniline (PANI)/PbI2 photoelectrode is prepared through the in situ oxidative polymerization of PANI on ATO, then PANI is used as an assistant for PbI2 deposition using the ionic adsorption deposition method. The chemical structural, morphological, electrical, and optical properties of the composite are confirmed using different analytical tools such as X-ray diffreaction (XRD), scanning electron microscope (SEM), transmision electron microscope (TEM), Fourier-transform infrared spectroscopy (FTIR), and UV-Vis spectroscopy. The prepared PbI2 inside the composite has a crystal size of 33 nm (according to the peak at 12.8°) through the XRD analyses device. SEM and TEM confirm the hexagonal PbI2 sheets embedded on the PANI nanopores surface. Moreover, the bandgap values are enhanced very much after the composite formation, in which the bandgap values for PANI and PANI/PbI2 are 3 and 2.51 eV, respectively. The application of ATO/PANI/PbI2 nanocomposite electrode for sewage splitting and H2 generation is carried out through a three-electrode cell. The measurements carreid out using the electrocehical worksattion under th Xenon lamp (100 mW.cm−2). The produced current density (Jph) is 0.095 mA.cm−2 at 100 mW.cm−2 light illumination. The photoelectrode has high reproducibility and stability, in which and the number of H2 moles is 6 µmole.h−1.cm−1. The photoelectrode response to different monochromatic light, in which the produced Jph decreases from 0.077 to 0.072 mA.cm−2 with decreasing of the wavelengths from 390 to 636 nm, respectively. These values confirms the high response of the ATO/PANI/PbI2 nanocomposite electrode for the light illuminaton and hydrogen genration under broad light region. The thermodynamic parameters: activation energy (Ea), enthalpy (ΔH*), and entropy (ΔS*) values are 7.33 kJ/mol, −4.7 kJ/mol, and 203.3 J/mol.K, respectively. The small values of ΔS* relted to the high sesnivity of the prepared elctrode for the water splitting and then the hydrogen gneration. Finally, a theoretical study was mentioned for calculation geometry, electrochemical, and thermochemistry properties of the polyaniline/PbI2 nanocomposite as compared with that for the polyaniline.

Saponification Value of Fats and Oils as Determined from 1H-NMR Data: The Case of Dairy Fats.

The saponification value of fats and oils is one of the most common quality indices, reflecting the mean molecular weight of the constituting triacylglycerols. Proton nuclear magnetic resonance (1H-NMR) spectra of fats and oils display specific resonances for the protons from the structural patterns of the triacylglycerols (i.e., the glycerol backbone), methylene (-CH2-) groups, double bonds (-CH=CH-) and the terminal methyl (-CH3) group from the three fatty acyl chains. Consequently, chemometric equations based on the integral values of the 1H-NMR resonances allow for the calculation of the mean molecular weight of triacylglycerol species, leading to the determination of the number of moles of triacylglycerol species per 1 g of fat and eventually to the calculation of the saponification value (SV), expressed as mg KOH/g of fat. The algorithm was verified on a series of binary mixtures of tributyrin (TB) and vegetable oils (i.e., soybean and rapeseed oils) in various ratios, ensuring a wide range of SV. Compared to the conventional technique for SV determination (ISO 3657:2013) based on titration, the obtained 1H-NMR-based saponification values differed by a mean percent deviation of 3%, suggesting the new method is a convenient and rapid alternate approach. Moreover, compared to other reported methods of determining the SV from spectroscopic data, this method is not based on regression equations and, consequently, does not require calibration from a database, as the SV is computed directly and independently from the 1H-NMR spectrum of a given oil/fat sample.

Rapid Opto-electrochemical Differentiation of Marine Phytoplankton.

The use of electro-generated oxidants in seawater facilitates the discrimination of different plankton groups via monitoring the decay in real time of their chlorophyll-a (chl-a) fluorescence signals following potentiostatic initiation of electrolysis in their vicinity (Yang M.Chem. Sci.2019, 10( (34), ), 7988-7993). In this paper, we explore the sensitivity of phytoplankton to different chemical species produced at various potentials in seawater. At low potentials, the oxidation of ca. millimolar bromide naturally present in seawater to hypobromous acid 'switches-off' the chl-a signal of individual Chlamydomonas concordia cells (green algae) located on the electrode surface within tens of seconds of the potential onset. At higher oxidative potentials, the oxidation of chloride and water produces oxidants (Cl2, OH, H2O2, etc.) that are also lethal to the plankton. To deconvolute the contributions to the response from the chemical identity of the oxidant and the amount of charge delivered to 'titrate' the individual living plankton using the loss of fluorescence as the 'end point', we introduce a ramped galvanostatic method. This approach enabled the controlled injection of charge applied to a bespoke electrochemical cell in which the plankton are immobilized on an electrode surface for rapid and sensitive measurement. It is shown that the number of moles (charge) of oxidants required to react leading to chl-a switch-off is independent of the chemical identity of the electro-generated oxidant(s) among hypobromous acid, chlorine, or water-derived oxidants. Comparative experiments between C. concordia and Emiliania huxleyi (where the latter are encapsulated by extracellular plates of calcium carbonate) show that significantly different amounts of absolute charge (moles of electro-generated oxidants) are required in each case to 'switch-off' the chl-a signal. The method provides the basis for a tool that could distinguish between different plankton cells within ca. 2 min including the setup time.

Production of biodiesel from waste cooking oil using heterogeneous catalyst

The world's oil reserves are running low, which makes the government also implement a mandatory B30 policy starting in early 2020. With this policy, it is necessary to develop energy by utilizing renewable energy such as vegetable oil that can be converted into biodiesel. Waste cooking oil is one of the vegetable oils that has the potential to be processed into biodiesel because the use of waste cooking oil in Indonesia is still not developed. In this study, we report the yield of biodiesel from waste cooking oil with variations in the ratio of the number of moles and weight of heterogeneous catalysts. Biodiesel is made by esterification and transesterification with a heterogeneous catalyst (CaO), then a separation process is carried out to separate the biodiesel produced from the by-product in the form of glycerol. The separated biodiesel is then analyzed for density, viscosity, flash point, and pour point. The results showed that the best biodiesel was at a mole ratio of 1:24 with 3% CaO catalyst. Based on the analysis data, this biodiesel has the largest yield of 72.49% with a viscosity value of 4.9806 cSt, a flash point value of 72.5 oC, a pour point value of 0 oC, and a density value of 0.8662 g/ml and calorific value. 8837,302 cal/gram. With the results of the analysis, that are in accordance with the quality standards of SNI 7182:2015.

New approach for starch dialdehyde preparation using microwave irradiation for removal of heavy metal ions from water

This work presents a new and simple approach to prepare Dialdehyde Starch (DAS) in one step under microwave irradiations and using, a mild and safer oxidizing agent, potassium iodate. Aldehyde content was evaluated to compare the synthesis results with DAS prepared using potassium periodate as an oxidizing agent for starch. To optimize the synthesis parameters of the new approach, the effect of the quantity of oxidizing agent and the effect of reaction time on the content of aldehyde in DAS were evaluated. According to the results, the optimized time was 10 min at the power of 300 W, and the number of moles of oxidizing agent was 0.014 mol per 2 g of starch. After that, DAS was used to prepare two Schiff bases by reaction with urea (DASU) and thiourea (DASTU), respectively. DAS, DASU and DASTU were characterized by FTIR, XRD, and SEM. Furthermore, DAS, DASU and DASTU were investigated for removing Cu(II), Pb(II), Hg(II), Cd(II), and Cr(III) ions from water. DAS showed the highest removal efficiency towards Pb(II) ions, whereas DASTU exhibited excellent ability for removing the Hg(II) ions. The removal efficiencies of DAS for Pb(II) ions and DASTU for Hg(II) ions are 95.25% and 89.45%, respectively from aqueous solutions containing 100 ppm of respective ions. Adsorption isotherm study suggests that adsorption follows Langmuir isotherm model, (correlation factors (R2) for Langmuir and Freundlich models for DAS/Pb are equal to 0.984 and 0.799, respectively, and for DASTU/Hg they are 0.995 and 0.813, respectively). The theoretical maximum adsorption capacity for DAS/Pb and DASTU/Hg are 245.09 and 180.83 mg/g, respectively.

Gas-solid flow characteristics in turbulent fluidized bed with variable gas velocity

In turbulent fluidized bed (TFB), the superficial gas velocity usually varies since chemical reactions can change the number of gas moles. However, information from the study without considering the variation of gas velocity is usually used to guide the design and operation of industrial TFB reactors. In order to reveal the difference of constant and variable gas velocity and to address the possible effect of without considering variation of gas velocity, experiment and three-dimensional Computational Fluid Dynamics (3D CFD) simulation were performed on the gas-solid flow characteristics in TFB. Results show that the nonuniformity of axial flow field can be overestimated while the nonuniformity of radial flow field can be underestimated without considering the variation of gas velocity for the system in which the number of gas mole increases due to chemical reactions. Such different flow hydrodynamics with and without considering the variation of gas velocity can be more clearly observed at higher solids handle capacity. CFD simulation results indicate that the presence of particle clusters can provide reliable explanations on the different flow behavior at constant and variable gas velocity. The particle tracer information and the residence time distribution (RTD) of gas phase indicate that the back-mixing of gas and solids can be overestimated without considering the variation of gas velocity. Results indicated that the guiding information from the constant gas velocity study can largely misguide the estimation of the conversion process if this guiding information is applied in the actual industrial process with the number change of gas moles in chemical reactions.

Engineering of tomato type VI glandular trichomes for trans-chrysanthemic acid biosynthesis, the acid moiety of natural pyrethrin insecticides

Glandular trichomes, known as metabolic cell factories, have been proposed as highly suitable for metabolically engineering the production of plant high-value specialized metabolites. Natural pyrethrins, found only in Dalmatian pyrethrum (Tanacetum cinerariifolium), are insecticides with low mammalian toxicity and short environmental persistence. Type I pyrethrins are esters of the monoterpenoid trans-chrysanthemic acid with one of the three rethrolone-type alcohols. To test if glandular trichomes can be made to synthesize trans-chrysanthemic acid, we reconstructed its biosynthetic pathway in tomato type VI glandular trichomes, which produce large amounts of terpenoids that share the precursor dimethylallyl diphosphate (DMAPP) with this acid. This was achieved by coexpressing the trans-chrysanthemic acid pathway related genes including TcCDS encoding chrysanthemyl diphosphate synthase and the fusion gene of TcADH2 encoding the alcohol dehydrogenase 2 linked with TcALDH1 encoding the aldehyde dehydrogenase 1 under the control of a newly identified type VI glandular trichome-specific metallocarboxypeptidase inhibitor promoter. Whole tomato leaves harboring type VI glandular trichomes expressing all three aformentioned genes had a concentration of total trans-chrysanthemic acid that was about 1.5-fold higher (by mole number) than the levels of β-phellandrene, the dominant monoterpene present in non-transgenic leaves, while the levels of β-phellandrene and the representative sesquiterpene β-caryophyllene in transgenic leaves were reduced by 96% and 81%, respectively. These results suggest that the tomato type VI glandular trichome is an alternative platform for the biosynthesis of trans-chrysanthemic acid by metabolic engineering.

Significant contribution of lightning NOx to summertime surface O3 on the Tibetan Plateau

Lightning generates nitrogen oxides (NOx) in the troposphere, an important precursor of tropospheric ozone (O3). The Tibetan Plateau (TP) is considered to be a global atmospheric background location with limited anthropogenic influences. However, the observed summertime surface O3 concentration on the TP is 25% higher than that in highly polluted regions (e.g., southern China). Previous studies have suggested that lightning-produced NOx (LNOx) can affect the concentration of surface O3. We used the Weather Research and Forecasting coupled with chemistry (WRF-Chem) model combined with satellite, ground-based, and airborne observations to evaluate the contribution of LNOx to the surface O3 budget on the TP. Our results showed that LNOx contributed approximately 15% of the surface NOx emission on the TP in summer. Accordingly, the contribution of LNOx to the summertime surface daily maximum 8-h average (MDA8) O3 on the TP was 9.3 ± 7.1 ppb, which was 17.5% ± 14.5% of the total concentration of the surface MDA8 O3. In addition, our study found that the number of moles of NO produced per lightning flash (LNOx production efficiency) significantly affected the surface concentration of NOx, OH, and MDA8 O3. Increasing the LNOx production efficiency (PE) from 0 to 330 mol NO flash−1 increased the concentration of MDA8 O3 by up to 20% on the TP. Our study revealed that lightning significantly affects the atmospheric chemical processes involving O3 on the TP.

The Influence of Electrolyte Type on Kinetics of Redox Processes in the Polymer Films of Ni(II) Salen-Type Complexes.

Electrodes modified with polymers derived from the complexes [Ni(salcn)], [Ni(salcn(Me))] and [Ni(salcn(Bu))] were obtained in order to study the kinetics of electrode processes occurring in polymer films, depending on the thickness of the films, the type of electrolyte and the solvent. FTIR and EQCM methods were used to determine the type of mass transported into polymer films during anode processes and the number of moles of ions and solvent. The rate of charge transport through films was determined by the cyclic voltammetry method, by the quantity cD1/2. It was shown that the charge transport was determined by the transport of anions. The kinetics were most efficient for poly[Ni(salcn(Bu))] modified electrodes, obtained from TBAPF6 and working in TBAClO4 and TBABF4. It was also shown that a solvent with a higher DN value and lower viscosity (MeCN) facilitated the transport of the charge through polymer films.

Effect of Au Plasmonic Material on Poly M-Toluidine for Photoelectrochemical Hydrogen Generation from Sewage Water.

This study provides H2 gas as a renewable energy source from sewage water splitting reaction using a PMT/Au photocathode. So, this study has a dual benefit for hydrogen generation; at the same time, it removes the contaminations of sewage water. The preparation of the PMT is carried out through the polymerization process from an acid medium. Then, the Au sputter was carried out using the sputter device under different times (1 and 2 min) for PMT/Au-1 min and PMT/Au-2min, respectively. The complete analyses confirm the chemical structure, such as XRD, FTIR, HNMR, SEM, and Vis-UV optical analyses. The prepared electrode PMT/Au is used for the hydrogen generation reaction using Na2S2O3 or sewage water as an electrolyte. The PMT crystalline size is 15 nm. The incident photon to current efficiency (IPCE) efficiency increases from 2.3 to 3.6% (at 390 nm), and the number of H2 moles increases from 8.4 to 33.1 mmol h−1 cm−2 for using Na2S2O3 and sewage water as electrolyte, respectively. Moreover, all the thermodynamic parameters, such as activation energy (Ea), enthalpy (ΔH*), and entropy (ΔS*), were calculated; additionally, a simple mechanism is mentioned for the water-splitting reaction.

THE DIFFERENTIAL THERMAL ANALYSIS OF COMPLEX CATALYTIC SYSTEM OF 50%Cu3(PO4)2•50%Ni3(PO4)2

The catalytic system of 50% Cu3(PO4)2∙50% Ni3(PO4)2 based on Copper (II) and Nickel (II) orthophosphates was synthesized by the coprecipitation method according to the method developed at the Department of Physical and Colloid Chemistry of Uzhhorod National University. The synthesized system was investigated by the method of differential thermal analysis. The obtained results can be interpreted in favor of the formation of a new phase, which is formed due to the equiatomic interaction of the initial components. Thus, a number of thermal effects different from Cu3(PO4)2∙3H2O and Ni3(PO4)2∙8H2O are observed on the corresponding thermogram. The only endothermic effect at 117 ° C is not recorded on the thermograms of the starting components. In the case of a solid solution or a simple mixture of phases based on starting phosphates, this effect should be observed at intermediate temperatures in the range from 129°C to 268°C. Probably, the newly formed phase, by the number of moles of water of crystallization, differs from the original individual orthophosphates. Information about a more accurate number of molecules of chemically bound water in hydrated forms of the synthesized complex copper-nickel phosphate catalyst will allow to establish the results of additional studies by derivatographic or gravimetric analyzes, which were not performed in this work. After dehydration with a further increase in temperature, no endothermic effect for a complex catalytic system is observed. Instead, four exothermic effects are recorded at once: the first two - at 456ºС and 564ºС (both insignificant in area), and the next two at slightly higher temperatures - 658ºС and 777ºС (larger in area). The effects at 564ºC and 658ºC can be attributed to the crystallization of dehydrated Cu3(PO4)2. The exoeffect at 777°C corresponds to the formation of the structure of dehydrated orthophosphate Nickel Ni3(PO4)2. Thus, the obtained experimental data of differential thermal analysis confirm the effective modifying role of Ni2+ ions on the structure, phase formation and a number of physicochemical properties of copper (II) phosphate in the synthesis of a complex oxide catalyst. This made it possible to obtain a new cheap and active complex acid catalyst with improved catalytic properties of 50 % Cu3(PO4)2∙50 % Ni3(PO4)2, which can be used for the process of converting natural gas components into valuable products of the chemical industry.&#x0D; Keywords: differential thermal analysis (DTA); catalysts; сopper (II) orthophosphate; nickel (II) orthophosphate; catalytic 50 % Cu3(PO4)2∙50 % Ni3(PO4)2 system.

Simple Approach for Reliable Prediction of Solubility of Polymers in Environmentally Compatible Solvents

This work presents a simple approach for predicting the solubility parameter (δ) of polymers. It is based on the number of moles of hydrogen, nitrogen, oxygen, sulfur, fluorine, and silicon atoms per mole of repeating unit structures as well as two correcting functions based on the contributions of hydrogen bonding and polar groups. The largest available experimental data including the δ values of 163 amorphous polymers and amorphous phases of semicrystalline polymers are used to derive and test the new model. Different statistical parameters are used to confirm the high reliability of the novel method through internal and external validations as well as by comparing with two of the best existing quantitative structure–property relationship (QSPR) approaches containing complex descriptors. Since the available QSPR methods are restricted to polymers with repeating unit structures −(C1H2–C2R3R4)–, the results of the new method are compared with the outputs of QSPR methods for 97 polymers. The value of root-mean-square error (RMSE) of the novel approach for external validation of test data (57 different polymers) is 0.91 MPa1/2, which is close to RMSE values of the computed outputs of two complex QSPR methods, that is, 0.90 and 0.88 MPa1/2.

Association effect on the density, viscosity and excess properties of fatty acid ester + alcohol mixtures: Experiment and modeling

The mixtures of fatty acid ester + alcohol are promising substitution fuels in engines. Due to their strong self- and cross-hydrogen bonds, the properties of these kinds of mixtures may show different characteristics from the fossil fuels composed of non-associating substances. In this work, the association effects on density and viscosity of fatty acid ester + alcohol are investigated from both experimental and theoretical aspects. The ethyl laurate + ethanol mixtures with 9 M fraction compositions are chosen, and the two properties are measured using a capillary viscometer system at temperatures from 313 K to 343 K and pressures up to 15 MPa. The positive excess volume and viscosity deviation of the mixtures are obtained, and the former is negligible compared to the experimental uncertainty. The Cubic-Plus-Association equation of state (CPA EoS) and the friction theory model are used to model the mixtures of ethyl laurate + ethanol. The relations of their self- and cross-associations to density, viscosity, and two excess properties (excess volume and viscosity deviation) are summarized. Different saturated fatty acid ester + 1-alcohol mixtures are also modeled with the CPA EoS. The variation characteristics of their viscosity deviations are analyzed and explained by their different association strength and the mole number of associated molecules.

Determining energetic characteristics and selecting environmentally friendly components for solid rocket propellants at the early stages of design

This paper has investigated the possibility to theoretically calculate a value of the specific impulse for highly energetic compositions using only two parameters – the heat of the reaction and the number of moles of gaseous decomposition reaction products. Specific impulse is one of the most important energetic characteristics of rocket propellant. It demonstrates the level of achieving the value of engine thrust and propellant utilization efficiency. Determining the specific impulse experimentally is a complex task that requires meeting special conditions. For the stage of synthesis of new promising components, the comparative analysis of energetic characteristics, forecasting the value of specific impulse, especially relevant are calculation methods. Most of these methods were first developed to determine the energetic characteristics of explosives. Since explosives and rocket propellants in many cases have similar energy content and similar chemical composition, some estimation methods can be used to assess the specific impulse of solid rocket propellant. The specific impulse has been calculated for 45 compositions based on environmentally friendly oxidizers (ammonium dinitramide, hydrazinium nitroformate, hexanitrohexaazaisowurtzitane) and polymer binders polybutadiene with terminal hydroxyl groups, glycidylazide polymer, poly-3-nitratomethyl-3-methyloxetane). It was established that the estimation data obtained correlate well with literary data. Deviation of the derived values of the specific impulse from those reported in the literature is from 0.4 % to 1.8 %. The calculation results could be used for preliminary forecasting of energetic characteristics for highly energetic compositions, selecting the most promising components, as well as their ratios.

Performance and sensitivity analysis of packed-column absorption process using multi-amine solvents for post-combustion CO2 capture

Although many novel multi-amine solvents with high CO2 solubility were reported, they have not yet been evaluated for the performance in CO2 absorption processes. In this study, the efficiency and inside profile of the packed-column CO2 absorption process using a novel multi-amine solvent were investigated by using a mathematical model. Three amine solvents were selected: 2-(2-aminoethylamino)-ethanol (AEEA) and diethylenetriamine (DETA) as multi-amine solvents and monoethanolamine (MEA) as a reference. Based on the 90% capture efficiency of flue gas CO2 from a coal-fired power plant, a sensitivity analysis using the liquid-to-gas ratio was conducted to minimize the energy consumption for CO2 capture. Based on the utilization of the same 30 wt% solvent, the lowest reboiler thermal energy achieved by the process using DETA was 3.242 GJ/tonCO2, which was 8.57% lower than that obtained when MEA was employed. In contrast, the process using AEEA required 7.04% higher energy than MEA. In the process modified by rich-solvent split for further enhancing efficiency, the DETA process could achieve 2.962 GJ/tonCO2, which reduced the reboiler duty by 16.8% from the MEA process. The CO2 capture performance of absorbents could not be evaluated not only by the absorption rate and capacity. Owing to the larger molecular weight of multi-amines than MEA, the performance of capture and regeneration was discussed with respect to the amine properties and number of amine moles in the solution. A well-selected multi-amine for a modified process configuration has considerable potential for improving the energy efficiency of CO2 capture.

Osmotically Enabled Wearable Patch for Sweat Harvesting and Lactate Quantification.

Lactate is an essential biomarker for determining the health of the muscles and oxidative stress levels in the human body. However, most of the currently available sweat lactate monitoring devices require external power, cannot measure lactate under low sweat rates (such as in humans at rest), and do not provide adequate information about the relationship between sweat and blood lactate levels. Here, we discuss the on-skin operation of our recently developed wearable sweat sampling patch. The patch combines osmosis (using hydrogel discs) and capillary action (using paper microfluidic channel) for long-term sweat withdrawal and management. When subjects are at rest, the hydrogel disc can withdraw fluid from the skin via osmosis and deliver it to the paper. The lactate amount in the fluid is determined using a colorimetric assay. During active sweating (e.g., exercise), the paper can harvest sweat even in the absence of the hydrogel patch. The captured fluid contains lactate, which we quantify using a colorimetric assay. The measurements show the that the total number of moles of lactate in sweat is correlated to sweat rate. Lactate concentrations in sweat and blood correlate well only during high-intensity exercise. Hence, sweat appears to be a suitable biofluid for lactate quantification. Overall, this wearable patch holds the potential of providing a comprehensive analysis of sweat lactate trends in the human body.