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Results for “PARAFFIN”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Shifting the Paraffin-to-Olefin Ratio and Gasoline Fuel Properties with Bimetallic BEA Zeolite Catalysts in Dimethyl Ether Homologation

Recent research on the production of HOG from DME over BEA zeolites suggests that this process offers an attractive alternative to traditional methanol-to-gasoline (MTG) technologies by operating at milder conditions and providing greater carbon efficiency 1. The HOG product is rich in branched olefins and paraffins, particularly triptane (2,2,3-trimethylbutane) which has high research- and motor-octane numbers (RON 112, MON 101), making it an ideal unleaded fuel or fuel additive for aviation or racing applications 2. RON and MON are important fuel metrics and research shows a correlation between them and paraffin and olefin content 3. Copper-modified BEA (Cu/BEA) is more active than HBEA . Research has identified that ionic Cu(I) species are active for alkane dehydrogenation whereas metallic Cu species responsible for hydrogenation chemistry 4. Here we report on the effect of including ionic Zn and Ni as a means of increasing the dehydrogenation activity of Cu/BEA in DME-to-HOG reactions. Bimetallic Cu-Zn/BEA and Cu-Ni/BEA catalysts were synthesized by first incorporating Ni or Zn by ion-exchange, followed by incipient-wetness impregnation of Cu. Similar metal loadings, acid site densities, and Bronsted/Lewis acid ratios were confirmed across all materials. All catalysts were tested in DME-to-HOG reactions with co-fed H2 at 200 degrees C and 15 psia with 1:1 DME:H-2 and DME weight-hourly space velocity of 2.2 gDME-gcat-1-h-1. Compared at similar turnover numbers (TON), Cu-Ni/BEA displayed similar activity to Cu/BEA however, exhibited greater hydrogenation activity as evidenced by the higher C5-8 P:O ratio. The Cu-Zn/BEA demonstrated decreased activity and the lowest P:O ratio, attributed to enhanced dehydrogenation activity at ionic Zn sites. For the HOG-range products (i.e., C5-8 hydrocarbon species), each catalyst had a 98-99 estimated RON, while the MON decreased with decreasing P:O ratio. Compared to Cu/BEA, these bimetallic catalysts demonstrate a unique balance of hydrogenation and dehydrogenation of the hydrocarbon products to access markedly different P:O product ratios without requiring a separate unit operation or a mixed catalyst bed.

09 BIOMASS FUELS↗
DOE OSTI2018

circRNA expression analysis in lung adenocarcinoma: comparison of paired fresh frozen and formalin-fixed paraffin-embedded specimens

Highlights: • First comparison of circRNA expression from paired fresh frozen and FFPE specimens. • Good correlation in circRNAs expression data utilizing fresh frozen or FFPE tissues. • Samples clustered correctly by differentially expressed circRNAs in either group. • Three differentially expressed circRNAs in lung cancers verified by qRT-PCR assay. • circRNA-miRNA-protein coding gene regulation network analyzed by bioinformatics tools. Circular RNA (circRNAs) is a novel class of endogenous non-coding RNAs which is widely involved in carcinogenesis. Archived formalin-fixed paraffin-embedded (FFPE) specimens represent valuable resources for cancer research. Currently there is a lack of systematic analysis on the feasibility of circRNAs expression analysis using FFPE samples. Here, we reported the first comparison study of circRNA expression from paired fresh frozen and FFPE specimens of lung adenocarcinoma. circRNAs expression of paired lung adenocarcinoma and adjacent normal samples, starting from either fresh frozen or FFPE materials, were analyzed via a high-throughput circRNA microarray. Hierarchical clustering was performed on samples. qRT-PCR was used to confirm the differentially expressed circRNAs. The circRNA regulation networks were built by bioinformatics tools for several candidate circRNAs. Our results demonstrated that there was a good correlation in circRNAs expression analysis utilizing fresh frozen or FFPE tissues. Tumors and adjacent normal tissues can be clustered correctly by the differentially expressed circRNAs in fresh frozen or FFPE groups. Furthermore, three differentially expressed circRNAs, hsa{sub c}ircRNA{sub 1}00421, hsa{sub c}ircRNA{sub 1}04329 and hsa{sub c}ircRNA{sub 1}01969 were verified by qRT-PCR assay. Bioinformatics analysis was also applied to predict the circRNA-miRNA-protein coding gene interaction network for each of above circRNAs. To the best of our knowledge, this is the first report demonstrating that the circRNAs microarray analysis, starting from FFPE specimens, is comparable with that based on fresh frozen samples. Therefore FFPE specimen represents a good substitute for fresh frozen tissue, especially when fresh frozen specimen is limited.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Plastic shrinkage of mortars cured with a paraffin-based compound – Bimodal neutron/X-ray tomography study

Early-age drying (immediately after casting) of mortars and the corresponding plastic shrinkage were studied using bimodal neutron/X-ray computed tomography. This novel, correlative 3D imaging mode enabled studying simultaneously and without any source of spurious perturbation the water migration and loss processes together with the corresponding deformations due to plastic shrinkage. Bimodal imaging opens up new possibilities for studying dynamic processes of coupled water transport and deformations in porous solids. The measurements were carried out on model systems (cylindrical mortar specimens with height of 19 mm). The study focused on the effect of a paraffin-based curing compound. Our results confirm that when the curing compound was applied directly onto the drying surface in a sufficient amount, both the evaporation rate and the rate of vertical displacement (settlement) were substantially reduced. The results shed a new light on the mechanisms of plastic shrinkage and the action of curing compounds.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Thermal energy storage composites with preformed expanded graphite matrix and paraffin wax for long-term cycling stability and tailored thermal properties

Harvesting solar energy, preventing hot spots in electronics, transport of temperature-sensitive materials, and capture and repurposing of thermal energy require a latent heat thermal energy storage (TES) system to store/discharge heat repeatedly. For the practical application of phase change material (PCM) composites within TES systems, reliable thermal performance throughout its operational lifetime is essential. Nevertheless, the reliability of thermal conductivity in multi-phase composites over relevant numbers (>10 3 ) of melt/freeze cycles has barely been studied, particularly for composites containing fillers for thermal conductivity enhancement. Here, we introduce a preform-type expanded graphite (EG)/paraffin wax composite possessing highly robust heat transfer and storage properties even after 10,000 melt/freeze cycles. To achieve such excellent reliability, comparative studies on the combined influence of fabrication process, particle size, EG vol%, binder amount, and compaction on both magnitude and robustness of thermal conductivity were undertaken. Our parametric study has yielded a trade-off between thermal conductivity and latent heat. Based on our modeling, 20 vol% EG approaches the case where all EG particles are well-connected thermally while 10 vol% EG is close to loosely connected fillers in the matrix. Thermal conductivity of our paraffin composites containing 20 vol% EG (25.1 W·m -1 ·K -1 ) is highest among other EG/paraffin composites without aligned EG in the literature. After 10,000 thermal cycling, negligible conductivity fading was observed for the 10 vol% EG composite, while reduction in latent heat remained within 10% for all 10, 14, 17 and 20 vol% EG samples. Here we anticipate this work provides insight on suitable recipe for desirable magnitude and robustness of thermal conductivity of EG/paraffin composites.

25 ENERGY STORAGE↗
DOE OSTI2025

Protecting air/moisture-sensitive samples using perdeuterated paraffin wax for solid-state NMR experiments under magic-angle spinning

Solid-state nuclear magnetic resonance (SSNMR) spectroscopy is a powerful technique for materials characterization, yet its application to air- and moisture-sensitive materials is often hindered by the difficulty in maintaining an inert environment during magic-angle spinning (MAS). This is particularly true for fast-MAS rotors that do not generally provide tight seals. Herein, we present a generalizable approach employing perdeuterated paraffin waxes—n-icosane-d42 and c-dodecane-d24—as protective embedding media to analyze sensitive organometallic catalysts using SSNMR. We demonstrate that these waxes significantly slow oxidative degradation under MAS conditions. Weak background 1 H and 13 C NMR signals from the waxes are effectively suppressed using double-quantum filtration and cross-polarization techniques. In conclusion, these findings offer a robust method for expanding the scope of SSNMR to air-sensitive systems, with implications for the structural study of reactive materials and catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Laser-pumped paraffin-coated cell rubidium frequency standard

We have realized and studied a rubidium atomic frequency standard based on a paraffin-coated cell, exhibiting a short-term frequency stability <3 Multiplication-Sign 10{sup -12} {tau}{sup -1/2} between {tau} = 1 and 100 s. Characterization of the wall-coating is performed by measuring the T{sub 1} and T{sub 2} relaxation times. Perturbations of the medium- to long-term clock stability, due to variations in the laser-intensity, laser frequency, the microwave power shift, and the shifts due to temperature variations are measured and analyzed. A method for reducing the intensity light-shift by detuning the laser frequency and the resulting improvement in clock stability is demonstrated. This work is of relevance for further improvements on Rb cell standards using anti-relaxation wall-coating technology.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Temperature Quenching and Fluorescence Depolarization of Carbon Nanodots Obtained via Paraffin Pyrolysis

A temperature effect on fluorescence intensity and polarization of a colloidal system of carbon nanodots in glycerol under linearly polarized pumping conditions is studied. Nanodots are obtained via pyrolysis of paraffin in nanopores of a mesoporous silica. An increase in temperature leads to quenching of nanodots fluorescence, and activation energy of the quenching process is assessed. An experimental relationship between the linear fluorescence polarization and temperature is described by the Levshin–Perrin equation, which takes into account the rotational diffusion of luminescent particles (fluorophores) in a liquid matrix. The size of fluorophores is noticeably smaller than that of carbon nanodots according to the Levshin–Perrin model. A difference between the dimensions of the fluorophore and the nanodot indicates that the small atomic groups responsible for luminescence of the nanodot possess high segmental mobility.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Effect of silver($\mathrm{I}$) ion reduction on the selectivity of olefins, paraffins, and aromatic compounds by gas chromatographic stationary phases consisting of silver($\mathrm{I}$) salts in ionic liquids

We report the olefin/paraffin selectivity offered by ionic liquid (IL) stationary phases can be enhanced through the addition of silver(I) ion, which is well-known to undergo selective complexation with unsaturated compounds. However, such stationary phases often suffer from the loss of chromatographic selectivity as silver(I) ion can be reduced to elemental silver. To maintain the separation performance of silver(I) ion/IL stationary phases, an understanding of factors and conditions that promote the reduction of silver(I) ion is needed. In this study, capillary gas chromatography columns featuring a stationary phase consisting of the 1-decyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C 10 MIM + ][NTf 2 - ]) IL impregnated with [Ag + ][NTf 2 - ] were examined to investigate the effects of temperature, hydrogen content in exposure gas stream, and time of heating/exposure events on olefin selectivity. Retention factors of representative analytes, such as C 6 olefins and paraffins as well as aromatic compounds, were measured after subjecting the columns to the aforementioned conditions, followed by an evaluation of selectivity factors over time. Selectivity factors of olefins and aromatic compounds were observed to decrease significantly when the stationary phases were heated to temperatures higher than 110°C as well as being subjected to mixed gas streams containing greater than 50 mol% of hydrogen. As constant column heating temperatures were applied under exposure gas mixtures containing hydrogen and nitrogen, a gradual decrease in analyte selectivity factors was observed under prolonged periods of time. However, application of a ternary gas mixture comprised of 25/50/25 mol% hydrogen/nitrogen/methane resulted in an increase in the 3-hexyne/cis-2-hexene selectivity when measured at 120°C for 60 h, due to a smaller decrease in the retention factor of 3-hexyne compared to cis-2-hexene.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Assessment of Training Performance, Degradation and Robustness of Paraffin-Wax Impregnated Nb 3 Sn Demonstrator Under High Magnetic Field

In the context of high-energy physics, the use of Nb 3 Sn superconducting magnets as a cost-effective and reliable technology depends on improvements in the following areas: long development and manufacturing cycles, conductor degradation after thermal cycling, long training, as well as a demonstration in accelerator magnets with a beam aperture of the full potential of modern Nb 3 Sn conductors. In short, performance, robustness, and cost are the three issues to be addressed. The Magnet Development project (MagDev) of the Swiss Accelerator Research and Technology initiative (CHART) at the Paul Scherrer Institute (PSI) aims to contribute to the solutions to each of these issues, re-thinking the manufacturing and design process. Here in our program, every innovation is to be validated by means of a panoply of fast-turnaround tools: from non-powered and powered samples and coils, tested under background field, to low-field subscale magnets and high field short prototypes. This work presents one element in this panoply of R&D vehicles: a stress-managed Nb 3 Sn coil called BigBOX, impregnated with paraffin wax, and tested, through a collaboration with the Magnet Development Program of the United States (US-MDP), in the background field of Brookhaven National Laboratory (BNL)’s common coils dipole DCC17.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Diverse high-pressure chemistry in Y-NH 3 BH 3 and Y–paraffin oil systems

The yttrium-hydrogen system has gained attention because of near-ambient temperature superconductivity reports in yttrium hydrides at high pressures. We conducted a study using synchrotron single-crystal x-ray diffraction (SCXRD) at 87 to 171 GPa, resulting in the discovery of known (two YH3 phases) and five previously unknown yttrium hydrides. These were synthesized in diamond anvil cells by laser heating yttrium with hydrogen-rich precursors—ammonia borane or paraffin oil. The arrangements of yttrium atoms in the crystal structures of new phases were determined on the basis of SCXRD, and the hydrogen content estimations based on empirical relations and ab initio calculations revealed the following compounds: Y 3 H 11 , Y 2 H 9 , Y 4 H 23 , Y 13 H 75 , and Y 4 H 25 . The study also uncovered a carbide (YC 2 ) and two yttrium allotropes. Complex phase diversity, variable hydrogen content in yttrium hydrides, and their metallic nature, as revealed by ab initio calculations, underline the challenges in identifying superconducting phases and understanding electronic transitions in high-pressure synthesized materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Medium-Chain Chlorinated Paraffins Measurements, SGP GIF, May 2023

This dataset contains measurements of medium-chain chlorinated paraffins (MCCPs) at 5-minute time resolution. The 6 most abundant ones are reported as well as the sum of all MCCPs measured. MCCPs were measured using a nitrate chemical ionization mass spectrometer at the ARM Southern Great Plains Guest Instrumentation Facility. Reported concentrations represent lower limit concentrations.

54 ENVIRONMENTAL SCIENCES↗