Diluent Concentration Research Articles

Reproductive toxicology of 2,4 dinitrophenol in boar sperm

The aim of this study was to evaluate the toxic effects of 2,4 dinitrophenol (DNP) on swine spermatozoa; particularly plasma membrane fluidity and integrity, mitochondrial function and motility, including oxidative stress parameters of lipid peroxidation and production of reactive oxygen species, when cooling to 17°C during 24 to 96h. We analyzed 22 ejaculates exposed to extender Beltsville Thawing Solution (BTS) (control) and in the same diluent concentrations of 0.01μM (T1), 0.1μM (T2), 1.0μM (T3) and 10μM (T4) of DNP. Shapiro Wilk test indicated the data was not normally distributed and means were compared using the Kruskal-Wallis test. Statistical analysis showed that DNP does not differ from the control, regardless of storage time, for any of the variables. Finally, quality parameters among the groups did not differ.

The influence of molecular weight distribution of industrial polystyrene on its melt extensional and ultimate properties

We analyze the linear viscoelastic behavior and the strain‐rate dependence of nonlinear viscoelastic as well as the ultimate extensional properties of industrially relevant linear polystyrene mixtures (PS). The studied materials comprise different miscible binary mixtures of a well entangled matrix and unentangled diluent resulting in bimodal molar mass distribution (MWD). We also analyze the effect of the diluent weight average molar mass (Mw) by comparison with a mixture having broad but monomodal MWD. We show that the dilution effect on linear rheological properties is in agreement with the theoretical value of unity for the dilution exponent. We further show that the processing window, expressed as the ability of the material to withstand a given load without loss of homogeneity during elongation or ultimate loss of cohesion, is affected differently depending on the diluent Mw and concentration. Finally, we conclude that the existence of strain hardening is not sufficient for complete characterization of extension dominated operations. Our results demonstrate that significant enhancement of strain hardening achieved by adding small‐Mw diluents is often accompanied by trade‐off with respect to failure behavior of these mixtures. POLYM. ENG. SCI. 56:1012–1020, 2016. © 2016 Society of Plastics Engineers

Dissipative particle dynamics study and experimental verification on the pore morphologies and diffusivity of the poly (4-methyl-1-pentene)-diluent system via thermally induced phase separation: The effect of diluent and polymer concentration

Dissipative particle dynamics (DPD) simulation was performed to construct the mesophase membrane morphologies of poly(4-methyl-1-pentene) (PMP) during thermally induced phase separation (TIPS). The PMP morphologies and their fluid diffusivities relationship was established using a mesoscale 3-D tetragonal-like structure construction. The effects of PMP concentration and the use of a single diluent (dioctyl phthalate, diphenyl ether, and dibutyl phthalate) or a mixed diluent on the pore morphology were compared. The diffusivity resistance was evaluated by comparing the mean square displacement of a hypothetical fluid bead through tetragonal-like morphologies in three normal directions. The 3-D morphology and density profile results revealed that larger pores were produced after TIPS when the PMP-diluent interaction was weaker. Radial distribution function analysis showed that poor diluent and high PMP concentration could form a coarsened structure with less interconnectivity, indicating more diffusion resistance. To verify DPD simulation results, PMP hollow fibre membranes (HFMs) were fabricated via TIPS, and HFM cross-sectional morphologies proved that the pore structures agreed with the DPD-simulation 3-D evolution diagram. The structure-fluid diffusivity resistance relationship was also confirmed by porosity measurements and gas permeation testing. The DPD simulation method is promising for the fabrication and design of gas-diffusive membranes, especially in terms of the rational selection of diluent and polymer concentration.

Chilled and post-thawed semen characteristics of buffalo semen diluted in tris extender enriched with date palm pollen grains (TPG)

The benefits of dates palm and their pollen grains in the human nourishment system have their consideration and importance in medical and nutritional point of view. The present study aimed to investigate a new perspective for the use of date palm pollen grains (DPPG) aqueous extract or infusion in preservation of chilled and frozen buffalo semen. Pooled buffalo semen were diluted by Tris-Citrate-Fructose egg yolk (TCFY) diluent (considered as control) and diverse concentrations of clarified soaked pollen grains in Tris-Citrate-Fructose (TCF) diluent in concentrations of 50, 100, 150, 200 and 250 mg DPPG/5 mL TCF. Five concentrations were kept without egg yolk (TPG) while other five concentrations contained 20% egg yolk (TPGY). Each of the two dilutions was enumerated according to the concentration of DPPG. Extended semen is then chilled (for 7 d) and cryopreserved. Motility, alive sperm and intact sperm membrane (HOST) % were recorded as characteristic sperm parameters. After 7 d of chilling, significant (P < 0.000 1) high percent of motile sperms was recorded for TPG 50, 100, 150, 200 and 250 (66.67, 65.00, 61.67, 61.67 and 63.33, respectively). After freeze thawing, TPGY 150 and 250 showed the significant (P < 0.000 1) high percent of motile sperms (43.75 and 45.00, respectively) while TPGY 100, 200, 250 and TPG 50, 150 revealed the high results concerning HOST (80.61, 83.99, 80.61, 88.33 and 83.33, respectively) whereas the highest alive sperm percentage was recorded with TPGY 150 (96.30) compared to the control. The aqueous cold infusion or extract of the DPPG, added to the TCF extender with or without the addition of egg yolk, proved its good preserving and maintaining capacity of chilled and thawed buffalo bull sperms which was expressed mainly by the sperm motility.

Stabilization of unstable detonation waves in mixtures of nitromethane with inert diluents

Mass velocity profiles of detonation waves in mixtures of nitromethane with acetone and methanol with added diethylenetriamine sensitizer were measured using a VISAR laser interferometer. It was found that even small, about 1%, concentrations of acetone and methanol, inert diluents, led to instability of the one-dimensional detonation front in nitromethane. The results of the experiment show that the use of the sensitizer is an effective method of flow stabilization and if the concentration of the inert diluent does not exceed 10%, the detonation front becomes stable with the addition of 1% diethylenetriamine. At a higher diluent concentration, the sensitizer does not suppress the instability but decreases the oscillation amplitude by several times. The addition of diethylenetriamine to the mixture has been found to increase the detonation velocity.

Effect of CO2 dilution on the structure and emissions from turbulent, non-premixed methane–air jet flames

This investigation gives a comparison of the variation of temperature and gas compositions in lifted, turbulent non-premixed methane–air jet flames firing vertically into still air with different carbon dioxide diluent concentrations in the fuel jet. The carbon dioxide mole fraction ranged from 0 to 0.22 and was varied with a fixed jet velocity so that dilution-induced extinction was achieved. The effect of the changes due to this dilution on the post-flame emissions was investigated. Similarly, visual observation of the changes in the flame structure in mixture fraction space at different diluent mole fraction has been studied. An examination of the changes in the flame length, lift-off height, flame temperature, composition, and on the emission indices of the species in the post-flame region were made. They showed an increase in the flame's lift-off height, a decrease in the overall flame length, a reduction in the flame temperature and a reduction in the NOx concentration at various levels of dilution of carbon dioxide in the fuel.

Studies of extractive removal of silver(I) from chloride solutions

For efficient recovery of silver(I) from chloride solutions, amine extractants were used. The effect of the type of diluent, extractant and chloride concentration, contact time and reextraction were studied. It was found that the best diluent for this process was xylene. Extraction of silver depended on concentration of hydrochloric acid, sodium chloride and extractant and additionally on the contact time. Reextraction of Ag(I) ions from the loaded organic phase showed that it can be removed only little using NH3·H2O, NaOH, NH4NO3, and NaNO3 as the stripping agents.

Performance of high temperature PEM fuel cell materials. Part 1: Effects of temperature, pressure and anode dilution

High temperature proton exchange membrane (HT-PEM) fuel cells operate most effectively at temperatures 160 °C or greater and can tolerate high carbon monoxide concentrations in fuel feeds. For practical mobile fuel cell systems, the ability to tolerate high levels of carbon monoxide enables a simplified integrated reformer fuel cell design, where a one-step reforming process can directly feed the fuel cell. This creates the potential for practical fuel cell systems to be designed that are capable of operating using an on-board hydrocarbon fuel. Hydrocarbon reforming processes (i.e., partial oxidation, steam reforming, or autothermal reforming) generate effluent gas compositions that typically contain various amounts of hydrogen, carbon monoxide, carbon dioxide, nitrogen, and water. While there are several studies that have examined the effects of CO dilution on HT-PEM fuel cell performance, there are very few that have examined the effects of other common reformate species, particularly while operating at varying temperatures and pressures. This work aims to fill the research gap in published data through evaluation of the performance exhibited by two HT-PEM membrane-electrode assembly (MEA) types, Advent's TPS©-based MEA and the BASF Celtec series MEA, based on acid-doped polybenzimidazole (PBI). In Part I of this series, the effects of temperature and pressure for various percentages of anode dilution were investigated. Temperatures and pressures were varied from 160 to 200 °C and 101.3–200 kPa, respectively. The effect of hydrogen diluted with nitrogen in the anode feed was examined with nitrogen concentrations up to 70%. Overall, the PBI MEA provided greater performance than the TPS for all tested conditions. Our results show that the performance loss due to high dilution levels can be wholly mitigated through an increase in operating temperature, pressure, or a combination thereof. For example, even at a dilution level containing 70% nitrogen, operating the cell at 200 °C and at 200 kPa provides the same power output as running the cell on pure hydrogen at 160 °C and at atmospheric pressure. This data can be used to model the performance effect of high diluent concentrations in the anode gas feed when developing an integrated reformer/fuel cell system.

N , N ′-tetrasubstituted succinamides as new molecules for liquid–liquid extraction of Pt(IV) from chloride media

Abstract Due to the increasing demand of platinum group metals (PGM’s), among which platinum, the search for new alternatives aiming to their extraction and recovery is nowadays of great importance. Thus, two N , N ′-tetrasubstituted succinamides, N , N ′-dicyclohexyl- N , N ′-dimethylsuccinamide (DMDCHSA) and N , N ′-dimethyl- N , N ′-diphenylsuccinamide (DMDPHSA) were synthesized and investigated, for the first time, as potential molecules for the liquid–liquid extraction of Pt(IV) from chloride solutions. According to the extraction and stripping results obtained in a single contact, these succinamides can be considered promising extractants for the recovery of platinum(IV) from hydrochloric acid media, since DMDCHSA is able to extract more than 95% Pt(IV) from 4 M HCl or higher concentrations, and DMDPHSA extracts 80% and 92% Pt(IV) from 6 M and 8 M HCl solutions, respectively. Furthermore, platinum(IV) can successfully be stripped through a simple contact with seawater: 93% Pt(IV) were recovered from DMDCHSA, while 60% stripping were obtained from DMDPHSA. For each compound, the time necessary to reach equilibrium, and the effects of the type of diluent and different extractant concentrations on the Pt(IV) extraction percentage were investigated. The loading capacity of DMDCHSA and DMDPHSA toward Pt(IV) was also evaluated, and the results show that both extractants present a very high loading capacity. In addition, data obtained from successive extraction-stripping cycles suggest a good stability pattern for both succinamides.

STUDIES OF SOLVENT EXTRACTION AND SUPPORTED LIQUID MEMBRANE WITH REACTIVE DYES FROM AQUEOUS SOLUTIONS USING ALIQUOT 336 AS CARRIER

The liquid-liquid extraction (LLE) and supported liquid membrane (SLM) studies of reactive dyes namely Gold Yellow (GYHE-R) and Reactive Green HE 4BD (RGHE-4BD) from aqueous solution using Aliquot 336 as the carrier has been investigated. Polytetrafluoroethylene (PTFE) membrane with 0.5 μm pore size has been used after impregnated with Aliquot 336 in dichloromethane. In liquid liquid extraction the following parameters had been optimized; pH of feed, diluent, carrier , strip and dye concentration and the same parameters have been applied to supported liquid membrane (SLM) study to transport dye from aqueous solution.The main advantages SLM study is; the extraction and stripping as single stage process and low consumption of carrier in the membrane phase compared to the solvent extraction process. The other parameters such as transport time, stirring speed and mechanism of dye transport has also studied by SLM. The percentage of transport of dye and flux rate increases with increasing time. The stability of membrane is satisfactory over 5 days.

Reactive extraction of phenol from aqueous solution using tri-octylamine dissolved in alkanes and alcohols

Extraction of phenol (0.053mol·kg−1) from wastewater is performed with trioctylamine (TOA: 0.023–0.091mol·kg−1) dissolved in four solvents (decane, octane, decan-1-ol, and octan-1-ol) at a constant temperature of 298K. The effect of TOA concentration and type of diluent on the removal efficiency of phenol have been derived. Results show that the neutral phenol molecule is effectively extracted by TOA into the organic phase at higher concentration of TOA than lower one. The equilibrium extraction results are presented in terms of distribution coefficient (D), degree of extraction (%E) and loading ratio (Z). Maximum value of D (=12.25) with %E=92.45% is observed at the highest concentration of TOA (0.091mol·kg−1) with octan-1-ol. A mathematical expression for the determination of D at equilibrium is presented by applying the mass action law. This model equation is used to graphically determine the equilibrium constant (KE) and the stoichiometric coefficient (n) of extraction. Also, the individual equilibrium constants (K11, K21 and K12) for the phenol–TOA complexes formed are estimated from the regression of the experimental results. The highest value of complexation constant (KE=2.3) is found with TOA in octan-1-ol. Phenol molecules are extracted by TOA+decane or octane with simultaneous formation of 1:1 and 2:1 solvates, and by TOA+decan-1-ol or octan-1-ol by making 1:1 and 1:2 complexes in the organic phase. The extraction power of TOA in terms of D decreases in the order of octan-1-ol>decan-1-ol>octane>decane.

The stabilization of unstable detonation waves for the mixture of nitromethane/methanol

Using a laser interferometer VISAR the measurements of the particle velocity profiles in detonation waves for nitromethane/methanol mixtures with additions of a sensitizer diethylenetriamine were conducted. It is shown that the detonation front in a mixture of nitromethane/methanol is unstable and sensitizer is an effective method for the flow stabilization. If the diluent concentration is less than 10%, the detonation front is stabilized by adding of 1% diethylenetriamine. At higher concentrations of methanol, the sensitizer does not reject instability, but the amplitude of oscillations decreases in several times. An increase of the limit concentration of methanol at the addition of diethylenetriamine to the mixture was found.

Preparation and characterization of novel vinyl ester formulations derived from cardanol

In this study, two commercially available epoxidized cardanol resins, NC 514 with approximately two epoxies per molecule and LITE 2513HP with approximately one epoxy per molecule were methacrylated and the methacrylated NC-514 resin (NC514VE) was used as the cross-linker unit and the mono-functional methacrylated LITE monomer (LITEVE) was used as the reactive diluent in both conventional DGEBA vinyl ester resin (DGEBAVE) and in NC514VE resin at changing concentrations. Resin formulations of NC514VE using styrene as the reactive diluent were also prepared. The methacrylated products were characterized via spectroscopic techniques like FT-IR and 1H NMR spectroscopy. The viscosities of the liquid resin mixtures at 30°C were examined and the curing behavior was analyzed via Differential Scanning Calorimetry (DSC). After the cure, the thermo-mechanical properties of the resins were determined via Dynamic Mechanical Analysis (DMA) and mechanical properties were determined via tensile tests. According to thermal gravimetric analysis (TGA) data, at 30wt% co-monomer content, the temperature of 5% degradation were in 270–300°C temperature region meaning that the samples were stable until this temperature range. The effect of the diluent content and the structures of the different monomers on both liquid resin and cured resin properties were also evaluated.

Effectiveness of Xenon as a Fire Suppressant Under Microgravity Combustion Environment

ABSTRACTThe ‘FLame EXtinguishment’ (FLEX) program conducted by NASA on board the International Space Station (ISS) has been assisting in developing fire-safety protocols for low gravity applications through microgravity droplet combustion experiments. A wide range of fuels, including alcohols and alkanes, have been studied in different ambient conditions that also encompass the use of various diluent species and concentrations. A prime focus of the work has been to observe the relative effectiveness of atmospheric composition and pressure changes on fire suppression under ‘reduced’ gravity conditions. Here, detailed numerical simulations are performed to investigate the combustion and extinction characteristics of isolated sphero-symmetric 1.0–2.0-mm diameter methanol droplets burning in xenon (Xe)-enriched environments. Comparisons of diluent behaviors under identical conditions using argon (Ar), carbon dioxide (CO2), and helium (He) as the alternative diluent to nitrogen are also reported. The predictions are compared against ISS experiments with good agreement and with less satisfactory agreement with the results published earlier by Shaw and Wei (2012). Xenon as diluent rather than nitrogen results in reduced burning rate, larger extinction diameter and counter intuitively, and prolonged burning time. The limiting oxygen index (LOI) for xenon is found to decrease significantly from that found with argon, carbon dioxide, or helium. The numerical analyses indicate that the lower thermal diffusivity of xenon is the principal factor responsible for the remarkably lower LOI. Water accumulation within the methanol droplet and its relevance to the extinction process is also discussed. It is concluded that the combined observation of elevated peak gas temperature, its slow decay due to minimal diffusive heat loss, and the exceptionally lower LOI value associated with xenon as a diluent all detract from its utility for suppressing fire concerns in reduced gravity applications.

Extraction of rare-earth elements(III) from nitric acid solutions with bis(diarylphosphorylmethyl)benzenes

Extraction of micro quantities of rare-earth elements(III) from HNO3 solutions as complexes with bis(diarylphosphorylmethyl)benzenes depending on the nature of organic diluent and HNO3 concentration in equilibrium aqueous phase was studied, the stoichiometry of extracted complexes was determined. The effect of structure of a bridge between two phosphine oxide fragments in an extractant molecule on the efficiency and selectivity of rare-earth elements(III) extraction was considered.

Perfectly stirred reactor model to evaluate extinction of diffusion flame

The paper focuses on developing and justification of the flame extinction model for large eddy simulations of under-resolved turbulent diffusion flames. The model is based on the perfectly stirred reactor (PSR) concept, in which the residence time is coupled with the local strain rate, and the radiative losses from the reaction zone are taken into account. The single-step global reaction of fuel oxidation is considered. A possible way to calibrate the kinetic parameters is that by fitting measured values of flame temperature and strain rate at diffusive extinction (blow-off). By comparing the simulation results with experimental data available for methane-air and heptane-air flames and with the published predictions made by the activation energy asymptotics for the ethylene-air flame, it is demonstrated that the PSR model is capable of evaluating flammability bounds of the diffusion flame, including high-strain blow-off and low-strain quenching (i.e., diffusive and radiative extinction). The confluence of these bounds is shown to produce the minimum extinguishing concentration of an inert diluent. For the flames diluted by nitrogen, carbon dioxide, water vapor, or argon, the minimum extinguishing concentrations predicted in this way by the non-adiabatic PSR model are shown to agree with the measured values. Possibility of formulating a unified extinction criterion, the Damköhler number, is confirmed.

Modified soybean oil as a reactive diluent: coating performance

A long oil alkyd was formulated with three soybean oil-based reactive diluents. Coatings properties were evaluated as a function of concentration of reactive diluent in the formulation. The tensile, thermomechanical, and general coating properties were evaluated. General coatings properties included crosshatch adhesion, pencil hardness, impact resistance, and solvent resistance. The siloxane and allyl ether-functionalized soybean oil enhanced the tensile modulus and crosslink density by 20% and 70%, respectively. Coatings with fluorine-functionalized soybean oil showed enhanced contact angle and solvent resistance, compared to alkyd coatings alone. The incorporation of reactive diluents in the formulation improved pencil hardness, while other general coating properties were not significantly affected.

Investigation of Extraction of 4-Oxopentanoic Acid by N,N-Dioctyloctan-1-amine in Six Different Diluents: Equilibrium Study

The present equilibrium study deals with the reactive extraction of 4-oxopentanoic acid [levulinic acid] from an aqueous solution by N,N-dioctyloctan-1-amine [tri-n-octylamine (TOA)] at a constant concentration of 0.573 kmol·m–3 in a wide range of diluents such as [n-decane, decane-1-ol, n-decane + decane-1-ol (1:1 v/v), toluene, 4-methylpentan-2-one (MIBK), and dichloromethane (DCM)] at isothermal conditions ((298 ± 1) K). The physical extraction of levulinic acid with pure diluents is also carried out. The effect of acid concentration (0.10 mol·kg–1 to 0.75 mol·kg–1) and type of diluent on the recovery of levulinic acid from aqueous solution are determined. Mathematical modeling based on mass action law is used to estimate overall equilibrium constants (KE), stoichiometry of reaction, and individual equilibrium constants (K11 and K21) for 1:1 and 2:1 complexes between acid and TOA. Further, the experimentally determined distribution coefficients (KD) are correlated predicted ones by the linear solvation...

Comparison of the performance of several recent syngas combustion mechanisms

A large set of experimental data was accumulated for syngas combustion: ignition studies in shock tubes (732 data points in 62 datasets) and in rapid compression machines (492/47), flame velocity determinations (2116/217) and species concentration measurements from flow reactors (1104/58), shock tubes (436/21) and jet-stirred reactors (90/3). In total, 4970 data points in 408 datasets from 52 publications were collected covering wide ranges of temperature T, pressure p, equivalence ratio φ, CO/H2 ratio and diluent concentration Xdil. 16 recent syngas combustion mechanisms were tested against these experimental data, and the dependence of their predictions on the types of experiment and the experimental conditions was investigated. Several clear trends were found. Ignition delay times measured in rapid compression machines (RCM) and in shock tubes (ST) at temperatures below 1000K could not be well-predicted. Particularly for shock tubes, facility effects at temperatures below 1000K could not be excluded. The accuracy of the reproduction of ignition delay times did not change significantly with pressure. The agreement of measured and simulated laminar flame velocities is better at low initial (i.e. cold side) temperatures, at fuel-lean conditions, for CO-rich and highly diluted mixtures. The reproduction of the experimental flame velocities is better when these were measured using the heat flux method or the counterflow twin-flame technique, compared to the flame cone method and the outwardly propagating spherical flame approach. With respect to all data used in this comparison, five mechanisms were identified that reproduce the experimental data similarly well. These are the NUIG-NGM-2010, Kéromnès-2013, Davis-2005, Li-2007 and USC-II-2007 mechanisms, in decreasing order of their overall performance. The influence of poorly reproduced experiments and weighting on the performance of the mechanisms was investigated. Furthermore, an analysis of local sensitivity coefficients was carried out to determine the influence of selected reactions at the given experimental conditions and to identify those reactions that require more attention in future development of syngas combustion models.

Biobased reactive diluent for UV-curable urethane acrylate oligomers for wood coating

Castor oil (CO)-based reactive diluent for UV-curable urethane acrylate oligomers was synthesized by the reaction of a CO with diethanolamine and the resultant product was subsequently reacted with allyl chloroformate. The reactive diluent was characterized by FTIR and 1H NMR techniques. This reactive diluent was incorporated in a urethane acrylate oligomer and photoinitiator at different weight fractions varying from 5 to 25 wt% for UV curing. The effects of reactive diluent concentrations on the viscosity of the formulations along with mechanical, chemical, and optical properties of UV-curable coatings were studied. Furthermore, the cured films were evaluated for glass transition temperature (Tg) determined by differential scanning calorimetry and thermal stability by thermogravimetric analysis. Gel content and water absorption of UV-cured films were evaluated.