Experimental and theoretical study of the adsorption of pure molecules and binary systems containing methane, carbon monoxide, carbon dioxide and nitrogen. Application to the syngas generation

This study takes place in the context of the use of a Synthesis Gas in Gas To Liquid process, liquid hydrocarbon production by conversion based on Fischer–Tropsch synthesis. Our aim is the process improvement by a selective recycling of the tail gas. So, we measure pure component isotherms for four gases (CO₂, CH₄, CO, N₂) of the tail gas until 2000 kPa and binary mixture (CO₂–CH₄; CO₂–N₂; CH₄–N₂) equilibria at 303.15 K and 400 and 950 kPa onto a ZSM-5 zeolite. We also predict the binary mixture equilibria by the Ideal Adsorbed Solution Theory (IAST) and the Vacancy Solution Model (VSM, Flory–Huggins and Wilson forms) and we obtain very good results. So not only binary mixture equilibria but also ternary and quaternary mixture adsorption can be predicted. With these data (experimental and simulated), we can conclude that the CO₂ is the most adsorbed component while N₂ is the least one. These two components can be separated from CH₄ and CO which are sent in the Synthesis Gas production step.     

Chemical Stability of α‐Tocopherol in Colloidal Lipid Particles with Various Morphologies

Colloidal lipid particles (CLPs) are promising encapsulation systems for lipophilic bioactives, such as oil‐soluble antioxidants that are applied in food and pharmaceutical formulations. Currently, there is no clear consensus regarding the relation between particle structure and the chemical stability of such bioactives. Using α‐tocopherol as a model antioxidant, it is shown that emulsifier type (Tween 20 or 40, or sodium caseinate) and lipid composition (tripalmitin, tricaprylin, or combinations thereof) modulated particle morphology and antioxidant stability. The emulsifier affects particle shape, with the polysorbates facilitating tripalmitin crystallization into highly ordered lath‐like particles, and sodium caseinate resulting in less ordered spherical particles. The fastest degradation of α‐tocopherol is observed in tripalmitin‐based CLPs, which may be attributed to its expulsion to the particle surface induced by lipid crystallization. This effect is stronger in CLPs stabilized by Tween 40, which may act as a template for crystallization. This work not only shows how the architecture of CLPs can be controlled through the type of lipid and emulsifier used, but also gives evidence that lipid crystallization does not necessarily protect entrapped lipophilic bioactives, which is an important clue for encapsulation system design. Practical Applications: Interest in enriching food and pharmaceutical products with lipophilic bioactives such as antioxidants through encapsulation in lipid particles is growing rapidly. This research suggests that for efficient encapsulation, the particle architecture plays an important role; to tailor this, the contribution of both the lipid carrier and the emulsifier needs to be considered.     

Photographing impact of molten molybdenum particles in a plasma spray

Plasma-sprayed molten molybdenum particles (∼40 μm in diameter) were photographed impinging at high velocity (∼140 m/s) on a glass substrate at room temperature. An optical sensor detected thermal radiation emitted by a droplet as it approached the substrate and activated a time delay unit. After a selected time interval, an Nd:YAG laser was triggered, emitting a 5 ns pulse that provided illumination for a charge-coupled device (CCD) camera to photograph the impacting droplet through a long-range microscope. By varying the delay before pulsing the laser, different stages of droplet deformation were recorded. Impacting droplets spread into a thin circular film that ruptured and broke into small fragments. An optical detector recording thermal radiation from the impacting droplet gave a signal that increased as the droplet spread out, reached a maximum when the liquid film began to rupture, and decreased as portions of the droplet recoiled because of surface tension and then flew out of view of the photodetector.     

Flattening and solidification of thermally sprayed particles

In this article, molybdenum particles were plasma sprayed on copper, zirconia, and glass substrates. The impact of the molten particles was monitored using a fast two-color optical fiber pyrometer focused on a small spot on the substrate surface. The apparent duration of the flattening process and the cooling speed, both determined from the pyrometer signals, were found to depend on the substrate conditions and to vary with coating thickness. The substrate material and its roughness were also found to influence the texture in the sprayed coatings. Furthermore, a transient thermal flow numerical model was used to compute reliable thermal histories of the impinging particles and the underlying lamellae, the interfacial thermal resistance being determined by comparison of experimental thermograms with computed ones.     

Friction coefficients in cold forging: A global perspective

Worldwide, at least twenty different tribological tests have been proposed for the empirical determination of friction coefficients in cold forging processes. Due to the varying test setups, means of measurement, and level of abstraction, the comparability of the outcomes is, however, disputable. Within this work, six established test principles are compared using identical tribological systems. Large differences between the empirically determined friction coefficients are observed but can be explained under consideration of the respective tribological loads. Additional investigations of an extrusion process reveal that friction models also have to take into account the varying local thickness of the lubricant film.     

The Composition of Crude Corn Oil Recovered after Fermentation via Centrifugation from a Commercial Dry Grind Ethanol Process

A study was conducted to examine the chemical composition of corn oil obtained after fermentation of corn to make fuel ethanol via centrifugation and compare its composition to that of corn germ oil (commercial corn oil) and experimental corn oils. The levels of free fatty acids in the post fermentation corn oil were high (11–16%), as previously reported. The levels of free phytosterols and hydroxycinnamate steryl esters (similar to oryzanol in rice bran oil) were higher than those of corn germ oil and were comparable to those of ethanol-extracted corn kernel oil. The levels of tocopherols were lower in post-fermentation oil than in either corn germ oil or ethanol extracted corn kernel oil. The levels of lutein and zeaxanthin in post-fermentation were much higher than those in corn germ oil and were comparable to those in ethanol-extracted corn kernel oil. Overall, exposure to all upstream processes of a fuel ethanol plant, including high-temperature liquefaction, saccharification and fermentation appeared to have the most notable effect on tocopherols, but it had little effect on the levels of free phytosterols, hydroxycinnamate steryl esters, lutein and zeaxanthin. It may be desirable to recover these valuable functional lipids prior to using the post-fermentation corn oil for industrial applications such as making biodiesel if a cost-effective recovery process can be developed.     

Partial Agonistic Actions of Sex Hormone Steroids on TRPM3 Function

Sex hormone steroidal drugs were reported to have modulating actions on the ion channel TRPM3. Pregnenolone sulphate (PS) presents the most potent known endogenous chemical agonist of TRPM3 and affects several gating modes of the channel. These includes a synergistic action of PS and high temperatures on channel opening and the PS-induced opening of a noncanonical pore in the presence of other TRPM3 modulators. Moreover, human TRPM3 variants associated with neurodevelopmental disease exhibit an increased sensitivity for PS. However, other steroidal sex hormones were reported to influence TRPM3 functions with activating or inhibiting capacity. Here, we aimed to answer how DHEAS, estradiol, progesterone and testosterone act on the various modes of TRPM3 function in the wild-type channel and two-channel variants associated with human disease. By means of calcium imaging and whole-cell patch clamp experiments, we revealed that all four drugs are weak TRPM3 agonists that share a common steroidal interaction site. Furthermore, they exhibit increased activity on TRPM3 at physiological temperatures and in channels that carry disease-associated mutations. Finally, all steroids are able to open the noncanonical pore in wild-type and DHEAS also in mutant TRPM3. Collectively, our data provide new valuable insights in TRPM3 gating, structure-function relationships and ligand sensitivity.     

Polyurethane methacrylate/silicone interpenetrating polymer networks synthesis,thermal and mechanical properties

The synthesis of an interpenetrating polymer network (IPN) combining a polyurethane methacrylate network (PUMA) and a silicone network is reported. The PUMA network is synthesized by UV-light cure. The silicone network is formed through a condensation between α, ω dihydroxy polydimethyl siloxane and γ-methacryloxypropyl trimethoxy silane (γ-MPS) as a cross-linking agent. The IPN is prepared by different mechanism: radical and condensation types. According to thermogravimetric analysis of the hybrid material, the thermal stability stayed unchanged but the kinetic of degradation changed. Tg decreased with increasing silica content. The thermal cure process under humid atmosphere influence properties just for PUMA/4.2%Si^UV+T. Condensation between γ-MPS decreases the penetration depth from 158 to 82 μm and increases the mechanical glass transition temperature from 106 to 141 °C.     

Temperature Measurement Challenges and Limitations for In-Flight Particles in Suspension Plasma Spraying

Suspension plasma spraying (SPS) acquires a significant interest from the industry. The deposited coatings using this technique were proved to have unique microstructural features compared to those built by conventional plasma spraying techniques. In order to optimize this process, in-flight particle diagnostics is considered a very useful tool that helps to control various spraying parameters and permits better coating reproducibility. In that context, the temperature of in-flight particles is one of the most important key elements that helps to optimize and control the SPS process. However, the limitations and challenges associated with this process have a significant effect on the accuracy of two-color pyrometric techniques used to measure the in-flight particle temperature. In this work, the influence of several nonthermal radiation sources on the particle temperature measurement is studied. The plasma radiation scattered by in-flight particles was found to have no significant influence on temperature measurement. Moreover, the detection of the two-color signals at two different locations was found to induce a significant error on temperature measurement. Finally, the plasma radiation surrounding the in-flight particles was identified as the main source of error on the temperature measurement of in-flight particles.