Alkenones as a promising green alternative for waxes in cosmetics and personal care products

© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Cosmetics 5 (2018): 34, doi:10.3390/cosmetics5020034.The move toward green, sustainable, natural products has been growing in the cosmetic and personal care industry. Ingredients derived from marine organisms and algae are present in many cosmetic products. In this study, a new green ingredient, a wax (i.e., long-chain alkenones) derived from Isochyrsis sp., was evaluated as an alternative for cosmetic waxes. First, the melting point was determined (71.1–77.4 °C), then the alkenones’ thickening capability in five emollients was evaluated and compared to microcrystalline wax and ozokerite. Alkenones were compatible with three emollients and thickened the emollients similarly to the other waxes. Then, lipsticks and lip balms were formulated with and without alkenones. All products remained stable at room temperature for 10 weeks. Lipstick formulated with alkenones was the most resistant to high temperature. Finally, alkenones were compared to three cosmetic thickening waxes in creams. Viscosity, rheology, and stability of the creams were evaluated. All creams had a gel-like behavior. Both viscosity and storage modulus increased in the same order: cream with alkenones < cetyl alcohol < stearic acid < glyceryl monostearate. Overall, alkenones’ performance was comparable to the other three waxes. Alkenones can thus offer a potential green choice as a new cosmetic structuring agent.This research was funded by the Washington Research Foundation and a private donor from friends of the Woods Hole Oceanographic Institution, grant number N-126478

The ABC130 barrel module prototyping programme for the ATLAS strip tracker

For the Phase-II Upgrade of the ATLAS Detector, its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100 % silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-25) and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.Comment: 82 pages, 66 figure

Real-Time Viscosity Measurements during the Accelerated Aging of Biomass Pyrolysis Oil

An oak bio-oil was aged at 90 °C using various times and methods. A novel method for aging bio-oils under shear is introduced and compared to standard (quiescent) aging experiments. In a hermetically sealed concentric cylinder rheometer, aging with shear for 8, 16, and 24 h showed increases in viscosity of 57, 300, and 720%, respectively. A similar increase in viscosity was observed after quiescently aging of sealed samples in a forced air oven (100, 120, and 740% after 8, 16, and 24 h, respectively). Another aging experiment under shear consisted of three 8 h aging steps with intermediate viscosity measurements. Viscosity increases were comparable to the 8, 16, and 24 h tests. A control experiment in the rheometer without shear found the increase in viscosity to be 30–50% less than the sheared experiments. The number-average molecular weight increased as samples were heat-treated at 90 °C for longer times. The water content showed small increases and decreases with aging, which was attributed to the heterogeneity of the sample. Real-time viscosity measurements during the 90 °C aging step found that the rate of viscosity growth decreased over time. An exponential decay function estimated the viscosity to be 90% of the steady-state viscosity after ∼3 days at 90 °C

Viscosity of Biomass Pyrolysis Oils from Various Feedstocks

Bio-oil is a renewable energy source that is produced from the pyrolysis of lignocellulosic biomass. The pyrolysis oils are emulsion-like fluids, containing aqueous and phenolic phases, and can be more than 400 times more viscous than water at 25 °C. A series of rheological tests were performed on a set of bio-oils from different feedstocks and pyrolysis conditions. In general, the viscosity of the oils was independent of the shear rate (i.e., Newtonian). However, some of the hardwood samples shear thin at lower temperatures (−5 °C) and high shears (>100 s⁻¹). Oscillatory frequency sweeps were also performed. All of the oil samples were found to be viscous liquids, and the loss modulus (<i>G</i>′′) was orders of magnitude greater than the storage modulus (<i>G</i>′). A strong dependence of viscosity upon the temperature showed that the viscosity of poplar and oak 500 °C oils increased over 220-fold between 55 and −5 °C. Water content and acidity were also measured and compared to viscosity. The water content was found to have a stronger effect on viscosity than acidity. Generally, the oils that had higher water contents had lower viscosities. Viscosity does not correlate with the acid number or pH. While the acid number and pH are independent measurements of the acidity of the bio-oils, no correlation between the acid number and pH was observed. The microstructure of the oils was investigated using optical microscopy and small-angle neutron scattering. Optical microscopy did not show discrete boundaries between the aqueous and organic phases. The neutron-scattering profiles showed that a fractal structure is present in two of the three oils studied

High Pressure Rheology of Hydrate Slurries Formed from Water-in-Mineral Oil Emulsions

Structure I methane hydrates are formed in situ from water-in-mineral oil emulsions in a high pressure rheometer cell. Viscosity is measured as hydrates form, grow, change under flow, and dissociate. Experiments are performed at varying water volume fraction in the original emulsion (0–0.40), temperature (0–6 °C), and initial pressure of methane (750–1500 psig). Hydrate slurries exhibit a sharp increase in viscosity upon hydrate formation, followed by complex behavior dictated by factors including continued hydrate formation, shear alignment, methane depletion/dissolution, aggregate formation, and capillary bridging. Hydrate slurries possess a yield stress and are shear-thinning fluids, which are described by the Cross model. Hydrate slurry viscosity and yield stress increased with increasing water volume fraction. As driving force for hydrate formation decreases (increasing temperature, decreasing pressure), hydrate slurry viscosity increases, suggesting that slower hydrate formation leads to larger and more porous aggregates. In total, addition of water to a methane saturated oil can cause more than a fifty-fold increase in viscosity if hydrates form

Rheology Modification and Enzyme Kinetics of High Solids Cellulosic Slurries

Chemical additives that reduce the yield stress and viscosity of pretreated corn stover slurries and also enhance the kinetics and overall conversion of cellulose during enzymatic saccharification were explored. Additives included polymers, proteins, and nonionic, anionic, and cationic surfactants. Rheological measurements assessed changes in the yield stress of the suspensions, and enzymatic saccharification experiments were conducted to assess the effect of the additives on enzyme kinetics. For high-solid slurries with an insoluble solids content of about 20%, a 3- to 4-fold reduction in the yield stress was observed upon addition of 2% (w/w) cetylpyridinium chloride (CPCl), cetyl trimethylammonium bromide (CTAB), sodium dodecylbenzene sulfonate (NaDBS), and sodium dodecyl sulfonate (SDS). However, the presence of bovine serum albumin (BSA) at the same concentration doubled the yield stress. Although NaDBS and SDS were both very effective at reducing the yield stress, their presence was very detrimental to the saccharification kinetics, cutting cellulose conversions from 80% to less than 20% over one week due to chemical inhibition of the enzymes. However, the surfactants CPCl and CTAB synergistically reduced the yield stress and increased the relative extent of cellulose conversion by up to 35% during the first 24 h of saccharification. The presence of BSA slightly reduced the extent of cellulose conversion. It is hypothesized that the increased rate of saccharification observed with the presence of CPCl and CTAB and the decreased rate observed with BSA are associated with the respective increases and decreases in the suspensions’ yield stresses, which in turn may affect the uniformity of mixing within the saccharification reactors. Of the modifiers tested, CPCl and CTAB appear to be the most efficacious, as they both reduce the yield stress at concentrations as low as 0.1% (w/w) and improve the kinetics of enzymatic saccharification. Lastly, the economic implications of rheology modifiers in a hypothetical lignocellulosic biomass-to-ethanol pilot facility are discussed

RHEOLOGICAL INVESTIGATION OF HYDRATE SLURRIES

The oil and gas industry is often plagued by the formation of clathrate hydrates in oil pipelines. While the industry originally had a heuristic of avoidance of clathrate hydrates they are moving to a heuristic of risk management. To successfully implement a risk management heuristic, time dependent phenomena of clathrate hydrate formation and flowline plugging must be known. The study of time dependent phenomena of formation and agglomeration are investigated using a TA Instruments AR-G2 rheometer with a pressure cell capable of operating at up to 13.8 MPa. Pressurized rheological experiments examine clathrate hydrates formed in situ. Both shear and oscillatory experiments have been conducted on the samples, giving flow and viscoelastic parameters. Shear experiments show sharp increases in viscosity upon clathrate hydrate formation indicating rapid aggregation. Transient oscillation experiments show a sharp increase in the elastic and loss moduli followed by a decrease in the loss moduli. Thus, both in situ clathrate hydrate formation and annealing are quantified. In addition these oscillatory measurements provided a novel technique for non-destructive investigation of clathrate hydrate aggregation over time.Non UBCUnreviewe

Shear-Induced Structures and Thickening in Fumed Silica Slurries

Chemical mechanical polishing (CMP) is an essential technology used in the semiconductor industry to polish and planarize a variety of materials for the fabrication of microelectronic devices (e.g., computer chips). During the high shear (∼1,000,000 s^–1) CMP process, it is hypothesized that individual slurry particles are driven together to form large agglomerates (≥0.5 μm), triggering a shear thickening effect. These shear-induced agglomerates are believed to cause defects during polishing. In this study, we examined the shear thickening of a 25 wt % fumed silica slurry with 0.17 M added KCl using <i>in situ</i> small-angle light scattering during rheological characterization (rheo-SALS). The salt-adjusted slurry displays a ∼3-fold increase in viscosity at a critical shear rate of 20,000 s^–1 during a stepped shear rate ramp from 100 to 25,000 s^–1. As the shear rate is reduced back to 100 s^–1, the slurry displays irreversible thickening behavior with a final viscosity that is 100-times greater than the initial viscosity. Corresponding rheo-SALS images indicate the formation of micrometer scale structures (2–3 μm) that directly correlate with the discontinuous and irreversible shear thickening behavior of the fumed silica slurry; these micrometer scale structures are 10-times the nominal particle diameter (∼0.2 μm). The scattering patterns from the 25 wt % slurry were corroborated through rheo-SALS examination of 27 and 29 wt % slurries (<i>C</i>_KCl = 0.1 M). All slurries, regardless of ionic strength and solids loading, display scattering patterns that are directly associated with the observed thickening behavior. Scattering was only observable during and after thickening (i.e., no scattering was detected in the absence of thickening). This work serves as the first <i>in situ</i> observation of micrometer scale structures within the fumed silica CMP slurry while under shear