Addition Of Diluent Research Articles

Effect of Different Reactive Diluents on PDMS-PEG Hydrogels Properties

Polydimethylsiloxane (PDMS) is commonly used biomaterials for tissue engineering due to inert and nontoxic properties. However, there is the main drawback of PDMS which it is hydrophobic in nature. To overcome this limitation, PDMS was crosslinked with polyethylene glycol (PEG) in order to enhance it hydrophilic property. In this study, the effect of allyl methacrylate (AMA) and PDMS-MA 1K as reactive diluents in the hydrogel fabrication was investigated. Firstly, PDMS-SiH and PDMS-MA that was synthesized and had been confirmed with Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). While for UV-crosslinked hydrogel, contact angle and swelling study were conducted. From the analysis, it was found that increasing in reactive diluents content increased the swelling with insignificant trend for contact angle result. Importantly, from this work the biocompatibility of produced PDMS-based hydrogel was enhanced with the addition of reactive diluents.

Samarium/cobalt separation by solvent extraction with undiluted quaternary ammonium ionic liquids

SmCo permanent magnets are used in the automotive and aircraft industries. They are preferable over NdFeB magnets for applications above 150 °C. End-of-life SmCo magnets are a valuable secondary source of cobalt and samarium. This study presents solvent extraction systems without addition of molecular diluents. Undiluted quaternary ammonium ionic liquids with chloride, thiocyanate and nitrate anions were used to extract metals from aqueous feed solutions with high chloride concentrations in order to separate the main metals (Sm/Co/Cu) present in SmCo magnets. A chloride/chloride extraction was compared with two split-anion extraction systems (i.e. chloride in the aqueous phase and either nitrate or thiocyanate in the organic phase). The advantage of split–anion extraction is that it can be done from a chloride solution, but with the extraction behavior of nitrate or thiocyanate solutions. Split-anion extraction was in this work applied to the separation of rare earth elements/transition metals instead of previous applications to the mixtures of rare earths. For all the systems, the selectivity of extraction, scrubbing and stripping from a multi-element solution were investigated. High separation factors (>7500) were found for Co/Sm separations. Co(II) and Cu(II) extracted in the chloride/chloride and chloride/nitrate systems could be stripped simply by water. However, stripping of the loaded ionic liquid in the chloride/thiocyanate system with water was not feasible. The extraction mechanism for the different ionic liquids was studied by extended X–ray absorption fine structure (EXAFS). A possible explanation on the extraction behavior of samarium ions in the presence of transition metal ions (cobalt and copper) is given.

An Experimental Investigation on the Combustion Process of a Simulated Turbocharged Spark Ignition Natural Gas Engine Operated on Stoichiometric Mixture

This research investigated the combustion process of an AVL Model LEF/Volvo 5312 single cylinder engine configured to simulate the operation of a heavy-duty spark ignition (SI) natural gas (NG) engine operated on stoichiometric mixture. The factors affecting the combustion process that were examined include intake pressure, spark timing (ST), and the addition of diluents including nitrogen (N2) and carbon dioxide (CO2) to the NG to simulate low British thermal unit (BTU) gases. The mixing of diluents with NG is able to slow down the flame propagation speed, suppress the onset of knock, and allow the engine to operate on higher boost pressure for higher power output. The addition of CO2 was more effective than N2 in suppressing the onset of knock and slowing down the flame propagation speed due to its high heat capacity. Boosting intake pressure significantly increased the heat release rate (HRR) evaluated on J/°CA basis which represents the rate of mass of fuel burning. However, its impact on the normalized HRR evaluated on %/°CA basis, representing the flame propagation rate, was relatively mild. Boosting the intake pressure from 1.0 to 1.8 bar without adding diluents increased the peak HRR to 1.96 times of that observed at 1.0 bar. The increase was due to the burning of more fuel (about 1.8 times), and the 12.9% increase in the normalized HRR. The latter was due to the shortened combustion duration from 23.6 to 18.2 °CA, a 22.9% reduction. The presence of 40% CO2 or N2 in their mixture with NG increased the peak cylinder pressure (PCP) limited brake mean effective pressure (BMEP) from 17.2 to about 20.2 bar. The combustion process of a turbocharged SI NG engine can be approximated by referring to the HRR measured under a naturally aspirated condition. This makes it convenient for researchers to numerically simulate the combustion process and the onset of knock of turbocharged SI NG engines using combustion process data measured under naturally aspirated conditions as a reference.

Development of tri-functional biobased reactive diluent from ricinoleic acid for UV curable coating application

Renewable based materials have come out as an environmentally friendly alternative to petrochemical based materials due to their sustainability, lower carbon footprints and often lesser price. A tri-functional acrylate monomer was synthesized from Ricinoleic acid (RA) and used as biobased reactive diluent along with an oligomer for a UV curable coating application. The ricinoleic acid was modified by using sodium methoxide catalyzed amidation with diethanolamine and converted into fatty amide based triol. This synthesized ricinamide triol (RTO) was further reacted with glycidyl methacrylate in presence of triphenylphosphine. The synthesized products were fully characterized by FTIR, GPC and end group analysis. The chemical structure of RTO and ricinamide triacrylate (RTA) was elucidated from 1H NMR, 13C NMR spectroscopy. In comparison, the commercial triacrylate was examined. The influence of addition of reactive diluents on the viscosity of oligomer with varying concentrations up to 10–30 wt% was studied using rheometer. The UV curing behavior of coatings was estimated by FTIR. The UV cured coatings was further characterized by DSC, XRD, and TGA analysis. The UV curing coatings were evaluated to determine the mechanical, physical and solvent resistance properties. The Biobased content, gel content and water absorption property of UV cured coatings was also examined.

Structure characterization of UV-curing PEG-b-PPG-b-PEG dimethacrylate cross-linked network

The molecular structure of a series of newly developed ultraviolet (UV) curable electrical contact stabilization materials, which contain polyethylene glycol (PEG)-block-polypropylene glycol (PPG)-block-polyethylene glycol (PEG) capped with methacrylate functional groups on both ends as the reactive oligomers and a methacrylated PEG as the reactive diluent was studied in detail. The effects of reactive diluents, including functionalities and compositions were investigated via a combination of dynamic mechanical analysis, differential scanning calorimetry, FT-IR spectroscopy and wide angle X-ray diffraction. All the films exhibit completely amorphous state at room temperature regardless of the composition or thermal history. However, a small amount of PPPDI molecular chains undergo crystallization upon slow cooling. This crystallization is completely inhibited when mixed with di-functional reactive diluents, owing to the high cross-link density. The introduction of mono-functional reactive diluents restricts but not completely prevents the crystallization process, which causes the resulting films to be difficult to crystallize to lower crystallinity levels. On the other hand, adding non-reactive diluents transforms the resulting films to become a fast-crystallizing material, as a result of the low cross-link density and a large portion of unreacted oligomers along with the unreactive component. Additionally, the degree of heterogeneity for the cross-linked networks is generally increased by the addition of reactive diluents. The molecular structures of PEG-b-PPG-b-PEG dimethacrylate cross-linked networks as well as mixed with different types of reactive diluents at both room temperature and crystallizing temperature were proposed.

Effect of CO2/N2 Dilution on Premixed Methane–Air Flame Stability Under Strained Conditions

The effects of adding N2 or CO2 as diluents to a premixed methane–air flames under strain conditions (associated with a stagnation plate) were examined for flame stand-off distance, stability, intensity, and global flame behavior at various equivalence ratios. A stagnation plate was used to simulate the flame behavior near a combustor wall that can help provide some insights into reducing thermal stresses and enhance combustor lifetime. Decrease in equivalence ratio at the same thermal intensity provided larger strain rates while maintaining a stable flame. At stoichiometric condition, a balance was provided between high strain rates and low oxygen concentration flames to mitigate the peak (maximum) flame temperatures, and the associated temperature-dependent pollutants emission, such as NOx, CO, and unburnt hydrocarbons. Higher thermal intensities provided higher strain rates; however, the addition of diluents impacted in destabilization of flame. The flame stand-off behavior occurred at lower strain rates, low thermal intensity, and increased equivalence ratios. CO2 dilution reduced flame intensity, increased flame stand-off distance and overall flame destabilization than that with N2 dilution.

The Impact of Modification of Epoxy Adhesive by Addition of Active Diluent on its Energetic and Adhesive Properties

The Impact of Modification of Epoxy Adhesive by Addition of Active Diluent on its Energetic and Adhesive Properties

Batch Reactor Study of the Effect of Aromatic Diluents to Reduce Sediment Formation during Hydrotreating of Heavy Oil

The effect of different aromatic diluents on sediment formation during the catalytic hydrotreating of heavy crude oil was studied. The experiments were carried out using a heavy crude oil with 11.69 °API and three aromatic streams from an industrial Fluid Cracking Catalytic plant: light cycle oil, heavy cycle oil, and decanted oil. All tests were performed in a batch reactor at reaction time of 2–4 h, reaction temperature of 380–420 °C, and addition of aromatic diluents in 5 and 10 wt % with respect to the crude oil. The reaction pressure and stirring rate were kept constant at 100 kg/cm2 and 1000 rpm, respectively. The results of the hydrotreating tests showed that the amount of sediment increases as the time and reaction temperature do, being the temperature the variable that has the greatest effect on sediment formation. Light cycle oil provides a greater suppression of sediments. This effect was attributed to the greater amount of total aromatic compounds (mainly diaromatics) able to keep asphaltenes ...

Effect of reactive and non-reactive diluents on thermal and mechanical properties of epoxy resin

The effect of reactive (polyethylene glycol) and non-reactive (toluene) diluents on thermal and mechanical properties (tensile strength, hardness and fracture toughness) of diglycidyl ether of bisphenol A epoxy resin (cured by triethylenetetramine) was investigated. The thermal stability and mechanical properties of the epoxy resin modified with reactive and non-reactive diluents at different wt% were investigated using thermo-gravimetric analyser, tensile test, hardness test and single-edge-notched bend test. A minor variation in thermal stability was observed for epoxy resin after addition of polyethylene glycol and toluene at 0.5 wt%; however, further addition of reactive and non-reactive diluents diminished the thermal stability. The addition of 10 wt% of polyethylene glycol in epoxy resin significantly enhances the tensile strength (∼12%), hardness (∼14%) and fracture toughness (∼24%) when compared to that of neat epoxy resin. In contrast, major drop in mechanical performance was observed after addition of toluene in epoxy. Furthermore, fracture surfaces were investigated under field emission scanning electron microscope to elucidate the failure mechanism.

PEG-functionalized ionic liquids: A class of liquid materials for highly efficient extraction of rare earth metals from aqueous solutions

Recycling of rare earth metals is important for their supply risk in the future. In this work, a greener and highly efficient liquid-liquid extraction strategy is presented for rare earth metals from aqueous solution with PEG-functionalized ionic liquids. The factors influencing the solvent extraction process such as phase volume ratio, equilibrium time, pH value of aqueous phase, alkyl chain length of the ionic liquids and temperature of the system were investigated systematically. It was found that under optimal conditions, the single-step extraction efficiency was >96.8% for the studied 11 kinds of rare earth metal ions Sc(III), La(III), Ce(III), Y(III), Nd(III), Sm(III), Gd(III), Dy(III), Ho(III), Yb(III) and Lu(III). After the extraction, about 100% of the rare earth metals could be stripped from the ionic liquids phases by using dilute aqueous oxalic acid, and the ionic liquids would be recovered and reused in the next extraction process. In addition, the extraction mechanism was investigated in some details, and an ion pair association mechanism was suggested. Since the extraction procedure was performed without saponification, addition of extra extractant, organic diluents or salt, the approach described here has the potential to be used as a sustainable strategy for the separation and enrichment of rare earths from complex matrixes.

Further Studies on the Recycle of Pyroprocessed Uranium

Based on the initial investigations for the recycle of pyroprocessed uranium from used nuclear fuel, additional research has been conducted for the continued reduction in radiation levels and transuranic content of the uranium products. Although the pyroprocessing technology is performed in a shielded facility, the products most likely will be handled in an unshielded environment by interested entities. A radiation level as low as possible is desired so that further operations can be undertaken directly with the uranium products without additional radiation dose to the involved personnel. The transuranic content of the uranium will affect the subsequent waste streams generated and thus also should be minimized. Several potential improvements to the process have been investigated and include reheating uranium products, removal of surface contamination, a pre-distillation salt-draining step, and reduction in diluent addition. The progress of these improvements will be discussed as well as plans for further study.

Investigation of dilution effect with N2/CO2 on laminar burning velocity of premixed methane/oxygen mixtures using freely expanding spherical flames

The main objective of this work was to measure the dilution effect of nitrogen and carbon dioxide on the unstretched laminar burning velocities and differential diffusional stability of premixed methane-oxygen mixtures at ambient conditions and different equivalence ratios. Freely expanding spherical flame method was used. The combustible mixture was prepared by following (100-Z)%CH4+2O2ϕ+Z%(N2/CO2) where Z corresponds to the percentage of diluent in the mixture by volume and ϕ refers to equivalence ratio. The percentage of N2/CO2 in the mixture was varied between 50–70%/30–50%. The equivalence ratio was varied from 0.6 to 1.4. Necessary stretch correction to the measured data was done following weak stretch theory. PREMIX with GRIMech3.0 was used to simulate all the experimental operating conditions. The addition of diluents has reduced the burning velocity of the mixture considerably due to the decrease in energy content of the mixture, increase in specific heat capacity and the corresponding reduction in the flame temperature and decrease in thermal diffusivity. At 50%N2/CO2 in the premixed methane-oxygen mixtures, the burning velocity measured with CO2 was 3.6 (average value estimated for all studied equivalence ratios) times smaller than the mixtures diluted with N2. Burning velocity was reduced by 88% due to the addition of 50%CO2 as compared to 0%CO2 in the combustible mixture and out of which reduction due to thermal effect was 81.5% and chemical effect (participation of added CO2 in the chemical reactions) was 6.5% (average value estimated for all studied equivalence ratios). For all the studied dilution cases, the burned gas Markstein length remains positive indicating that the mixtures were stable towards the differential diffusion effects. Agreement of burning velocities obtained between PREMIX with GRIMech3.0 and measurements was not good at lower levels of diluents. Based on the literature, a new species, and few elementary reactions were added to original GRIMech3.0. By doing sensitivity analysis, kinetic parameters of some elementary reactions were also modified. Simulations with the modified GRIMech3.0 showed good agreement with most of the experimental data.

THE ROLE OF DILUENTS IN MAINTAINING QUALITY OF BULL SPERM DURING FREEZING

This study aimed to determine the effect of diluent in maintaining the quality of bull sperm during freezing and physiological processes of bull sperm that occur during freezing. This research was conducted by observing samples of frozen bull sperm that uses diluents, as well as through the assessment of data research with assessment parameters such as macroscopic and microscopic assessment of cattle semen. Data were analyzed using descriptive statistical analysis. The results of this study indicate that the ratings fresh semen is done in two ways, namely macroscopically and microscopically. Grossly obtained volume of average ejaculate of 6 ml with a beige color and acidity levels on average 5.8. The concentration used is 'medium' which is a category of consistency and decent for further processing until the stage of freezing to rethawing. Microscopic assessment that includes an average frequency of motility in the fourth shelter is 70% with 3+ mass motility, percentage of live of fresh semen was obtained in this study was 80%. This value is the percentage of normal life. Based on these results it was concluded that the addition of diluents can reduce the rate of loss of quality (motility and percentage of survival) of bull sperm during the stages of preservation. Andromed diluent best in reducing the rate of decline in the quality of bull sperm during the stages of preservation

Development of 3D printable formulations containing CNT with enhanced electrical properties

This study demonstrates the feasibility of printing 3D composite objects based on acrylic photocurable formulations containing CNTs, by using an unmodified commercial DLP-printer. In the preliminary investigations, the most suitable formulation was developed. Viscosity and dispersion stability were adjusted by the addition of a reactive diluent to the acrylic formulation. FT-IR analyses in real time and photorheology tests allowed finding the best composition and printing parameters.Printing conditions were adjusted to get 3D structures from formulations with a content up to 0.3 wt % of CNTs. The presence of the filler causes a decrease of the crosslinking density, which could be overcome using higher intensity light sources. Electrical conductivity measurements performed on the printed samples give promising results for the use of the developed formulation for the building of 3D structures with electrical properties.

Graphite-to-Graphene: Total Conversion.

The rush to develop graphene applications mandates mass production of graphene sheets. However, the currently available complex and expensive production technologies are limiting the graphene commercialization. The addition of a protective diluent to graphite during ball-milling is demonstrated to result in a game-changer yield (>90%) of defect-free graphene, whose size is controlled by the milling energy and the diluent type.

Numerical simulation of thermal runaway and inhibition process on the thermal polymerization of styrene

In order to achieve safer operating conditions of styrene polymerization process and effective inhibition of runaway reaction, computational fluid dynamics (CFD) technology is applied to simulate the thermal polymerization of styrene. A three-dimensional geometry model of the stirred reactor is established with a tool of SolidWorks. The computational model is carried out with a commercial CFD code (FLUENT). The effect of the viscosity, the impeller speed, the temperature probe location and the diluent addition location are investigated. The simulation results indicate that the three-dimensional model is useful for revealing the distribution of temperature and divergence of thermal runaway and inhibition process on the thermal polymerization of styrene.

Effects of Diluent on Mechanical Properties of Hollow Glass Microsphere Reinforced Epoxy Resin Composite

In order to improve the mechanical properties of hollow glass microspheres (HGMs) reinforced epoxy resin composite, diluent was added in the system of epoxy resin. The results revealed that more HGMs can be filled in the epoxy resin when appropriate amount diluent was added in the system, thus composite with relative low bulk density 0.70g/cm3 and high compressive strength 71.85MPa was obtained. It was due to that the diluent reduce the viscosity of the epoxy resin, which ensures uniform wetting of the fillers and enables more HGMs to be filled in resin. Besides, addition of diluent improved the adhesive strength between the epoxy resin and HGMs, making the composite having a relative high specific strength and can be used in weight sensitive filed.

Oxidation behavior of β-SiAlON powders fabricated by combustion synthesis

The present study presents the effect of addition of diluents on the crystal morphologies and the impact on the oxidation resistance of β-SiAlON powders obtained from combustion synthesis method. Pure β-SiAlON were synthesized with diluents. It was observed by SEM that the diluents resulted in the transformation from large hexagonal column-shaped crystals to fine isotropic grains. Oxidation experiments were conducted by thermogravimetric analysis (TGA) in the temperature range from 1200°C to 1400°C. The TGA results indicated that oxidation was controlled by mixed chemical reaction and diffusion process. The chemical reaction step was found to be rate-controlling at low oxidation temperatures (1200°C and 1300°C), while at high temperature (1400°C), diffusion was found to control the reaction rate. Oxidation products were investigated by X-ray Diffraction (XRD) analysis and found to be made up of SiO2, Al2O3. This research aims to provide guidance for the fabrication of β-SiAlON by combustion synthesis, thus facilitating its further application in high temperature industry.

Effects of argon/nitrogen dilution on explosion and combustion characteristics of dimethyl ether–air mixtures

In this study, an investigation of the explosion parameters, which include maximum explosion pressure (pmax), maximum rate of pressure rise (dp/dt)max, and combustion characteristics, i.e., laminar burning velocity (SL), activation temperature (Ta) and Zel’dovich number (Ze) of dimethyl ether (DME)–air–argon/nitrogen mixtures are systematically carried out. The dilution effects on the explosion and combustion characteristics are also explored through the addition of two diluents, i.e., argon (Ar) and nitrogen (N2), into the DME–air mixture. It is found from experiment that, the explosion parameters of fuel-lean and fuel-rich mixture exhibit different behaviors. For the fuel rich mixture, pmax decreases with increasing amount of Ar and N2 dilution, and a significant drop of (dp/dt)max is observed as the amount of added diluent increases. For the fuel lean mixture, pmax is first increased with increasing diluent, afterwards it decreases as inert gas dilution ratio larger than a critical value, it is also found (dp/dt)max fluctuates with more addition of diluent. The present results also confirm that SL decreases more abruptly in the DME–air mixtures with dilution of N2 than with Ar, which indicates that the increase in density dominates over the retarding effect for laminar burning velocity in the cases of inert gases dilution. The activation temperature of DME–air–Ar is larger than DME–air–N2 at the same condition, which demonstrates N2 dilution is more sensitive than N2 on the suppression of chemical reaction. Results illustrate that Ze goes up with the increase of dilution ratio, and the values of Ze for argon diluted mixtures are larger than that of nitrogen diluted.

Relationship Between the Rate Performance of Rechargeable Lithium-Sulfur Batteries and the Local Viscosity Change at the Interface Between the Electrode and Li[N(CF3SO2)2]-Glyme Solvate Ionic Liquid

Sulfur is one of the attractive candidates as a positive electrode material because of the high theoretical specific capacity and the low cost. However, the dissolution of the intermediate lithium polysulfide, Li2S x , into the organic electrolyte leads to the rapid capacity fading and the low coulomb efficiency. The equimolar mixtures of lithium bis(trifluoromethylsulfonyl)amide (LiTFSA) and glyme (CH3-O-(CH2-CH2-O) n -CH3) are liquid at ambient temperature and are classified as a solvate ionic liquids because of the low vapor pressure, the wide electrochemical potential window, and the acceptable ionic conductivity[1]. Moreover, the solubility of Li2S x is known to be low due to the low donor ability of the LiTFSA-glyme solvate ionic liquid, resulting in enabling the more than 400-cycle stable charge-discharge operation of sulfur/carbon composite electrode in 50:50 mol% LiTFSA-triglyme (n=3) [2]. While the viscosity of the LiTFSA-glyme solvate ionic liquid is generally high, the addition of such non-flammable diluent as 1,1,2,2–tetrafluoroethyl 2,2,3,3–tetrafluoropropyl ether (HFE), which does not affect the complex cation structure, decreased the viscosity, leading to the improvement of the rate performance of the cell due to the increase in the diffusivity of Li+ in the electrolyte[2]. In particular, the charging reaction of Li-S battery (Li+extraction from the lithiated sulfur electrode), could be improved by adding HFE. The electrochemical quartz crystal microbalance (EQCM) is often used for the in-situ monitoring of the electrode mass. Moreover the change in the viscosity (η) and density (ρ) of the electrolyte near the electrode can be estimated using an impedance technique EQCM. We have already reported that the drastic changes in the local viscosity of 50:50 mol% LiTFSA-triglyme were observed during deposition and dissolution of lithium metal using an EQCM [3]. The change could be explained by the concentration distribution of Li+ in the diffusion layer and the transient change in the dissolved state of Li+. In this study, the EQCM measurements were conducted in 50:50 mol% LiTFSA-tetraglyme (n=4) solvate ionic liquid with and without HFE to compare the local physical property of the electrolyte during deposition and dissolution of lithium metal. The resonance resistance of a quartz crystal electrode is known to reflect the local viscosity and density of the contacting electrolyte on the electrode. The resistance decreased during deposition of Li and largely increased during dissolution of Li, and decayed toward the initial value after the interrupt of the current. The magnitude of the change in the resistance became small with addition of HFE. This indicated the local change in ηρ value due to the concentration distribution of Li+was suppressed in the presence of HFE. This work was partially supported by the Advanced Low Carbon Technology Research and Development Program (ALCA) from the Japan Science and Technology Agency (JST) and Keio Leading-edge Laboratory of Science and Technology (KLL). [1] T. Tamura et al., Chem. Lett., 39, 753 (2010). [2] K. Dokko et al., J. Electrochem. Soc., 160, A1304 (2013). [3] N. Serizawa et al., J. Electrochem. Soc., 160, A1529 (2013).