scholarly journals High–flux Composite PTMSP Membranes with Long–term Stable Characteristics at Elevated Temperatures and Pressures

2012 ◽  
Vol 44 ◽  
pp. 782-783 ◽  
Author(s):  
G. Dibrov ◽  
E. Novitskii ◽  
V. Vasilevskii ◽  
S. Bazhenov ◽  
V. Volkov
Keyword(s):  
Elevated Temperatures ◽  
High Flux

scholarly journals CO Detection Investigation at High Temperature by SiC MISFET Metal/Oxide Gas Sensors

Proceedings ◽  
2021 ◽  
Vol 56 (1) ◽  
pp. 41
Author(s):  
Lida Khajavizadeh ◽  
Anita Lloyd Spetz ◽  
Mike Andersson
Keyword(s):  
High Temperature ◽  
Gas Sensors ◽  
Elevated Temperatures ◽  
Long Term Stability ◽  
Stability Performance ◽  
Catalytic Metal ◽  
Co Detection ◽  
Effect Transistor ◽  
Metal Oxide Gas Sensors

In order to investigate the necessary device improvements for high-temperature CO sensing with SiC metal insulator semiconductor field effect transistor (MISFET)-based chemical gas sensors, devices employing, as the gas-sensitive gate contact, a film of co-deposited Pt/Al2O3 instead of the commonly used catalytic metal-based contacts were fabricated and characterized for CO detection at elevated temperatures and different CO and O2 levels. It can be concluded that the sensing mechanism at elevated temperatures correlates with oxygen removal from the sensor surface rather than the surface CO coverage as observed at lower temperatures. The long-term stability performance was also shown to be improved compared to that of previously studied devices.

scholarly journals Comparative analysis of the long-term effect of two families of high-flux polysulfone dialysers on platelet count: a retrospective cross-sectional study

2017 ◽  
Vol Volume 13 ◽  
pp. 1415-1422 ◽  
Author(s):  
Rosaria Del Giorno ◽  
Lorenzo Berwert ◽  
Silvio Pianca ◽  
Giorgia Bianchi ◽  
Olivier Giannini ◽  
...  
Keyword(s):  
Platelet Count ◽  
Comparative Analysis ◽  
Cross Sectional Study ◽  
Term Effect ◽  
High Flux ◽  
Sectional Study ◽  
Cross Sectional ◽  
Long Term Effect

Technology Focus: Wellbore Tubulars (July 2021)

2021 ◽  
Vol 73 (07) ◽  
pp. 50-50
Author(s):  
Robello Samuel
Keyword(s):  
Geothermal Energy ◽  
Elevated Temperatures ◽  
Clean Energy ◽  
Well Integrity ◽  
The Future ◽  
Geothermal Wells ◽  
Abandoned Wells ◽  
Thermal Simulations ◽  
Technology Focus

How we think about the future of the pipe industry must evolve. How must tubular design and manufacturing change as we transition to clean energy? Geothermal energy is an area that needs attention and, further, needs very specific attention on tubulars. Tubulars are an important component in the construction of geothermal wells, and we must align our requirements for geothermal energy. Some of the main challenges encountered in geothermal wells are corrosion and scaling. Moreover, temperature becomes a major consideration for tubulars, even more so with the temperature excursion during geothermal production. Perhaps the critical aspect in the design of the geothermal wells involves casing selection and design. Beyond manufacturing casing pipes to withstand these problems, considering the manufacturing of other components, such as connections, float collars, and float shoes, also is essential. Thermal expansion and thermal excursion of casings are well-integrity concerns; thus, casing design is important for long-term sustainability of geothermal wells. Apart from thermal simulations, guidelines and software are needed to undergird the designs to withstand not only temperature excursions but also thermomechanical and thermochemical loadings. Engineered nonmetallic casings also provide an alternative solution because they provide the desired strength and corrosion resistance in addition to meeting the goals of sustainability. Undoubtedly, the future of the tubular industry is going to be revitalized. The question now is how we can retrofit existing abandoned wells for this purpose. Recommended additional reading at OnePetro: www.onepetro.org. SPE 199570 - Special Considerations for Well-Tubular Design at Elevated Temperatures by Gang Tao, C-FER Technologies, et al.

Rational Design of Organic Electro-Optic Materials

2001 ◽  
Vol 708 ◽  
Author(s):  
Alex Jen ◽  
Robert Neilsen ◽  
Bruce Robinson ◽  
William H. Steier ◽  
Larry Dalton
Keyword(s):  
Wavelength Division Multiplexing ◽  
Material Properties ◽  
Electrostatic Interactions ◽  
Rational Design ◽  
Elevated Temperatures ◽  
Optical Loss ◽  
Quality Factors ◽  
Electro Optic ◽  
Lattice Hardening

ABSTRACTA number of material properties must be optimized before organic electro-optic materials can be used for practical device applications. These include electro-optic activity, optical transparency, and stability including both thermal and photochemical stability. Exploiting an improved understanding of the structure/function relationships, we have recently prepared materials exhibiting electro-optic coefficients of greater than 50 pm/V and optical loss values of less than 0.7 dB/cm at the telecommunication wavelengths of 1.3 and 1.55 microns. When oxygen is excluded to a reasonable extent, long-term photostability to optical power levels of 20 mW has been observed. Photostability is further improved by addition of scavengers and by lattice hardening. Long-term (greater than 1000 hours) thermal stability of poling-induced electro-optic activity is also observed at elevated temperatures (greater than 80°C) when appropriate lattice hardening is used. The successful improvement of organic electro-optic materials rests upon (1) attention to the design of chromophore structure including design to inhibit unwanted intermolecular electrostatic interactions and to improve chromophore instability and (2) attention to processing conditions including those involved in spin casting, electric field poling, and lattice hardening. A particularly attractive new direction has been the exploitation of dendrimer structures and particularly of multi-chromophore containing dendrimer structures. This approach has permitted the simultaneous improvement of all material properties. Development of new materials has facilitated the fabrication of a number of prototype devices and most recently has permitted investigation of the incorporation of electro-optic materials into photonic bandgap and microresonator structures. The latter are relevant to active wavelength division multiplexing (WDM). Significant quality factors (greater than 10,000) have been realized for such devices permitting wavelength discrimination at telecommunication wavelengths of 0.01 nm.

Long-Term Stability of Aluminum Oxide Based Surface Passivation Schemes Under Illumination at Elevated Temperatures

2017 ◽  
Vol 7 (5) ◽  
pp. 1197-1202 ◽  
Author(s):  
Tim Niewelt ◽  
Wolfram Kwapil ◽  
Marisa Selinger ◽  
Armin Richter ◽  
Martin C. Schubert
Keyword(s):  
Aluminum Oxide ◽  
Elevated Temperatures ◽  
Surface Passivation ◽  
Term Stability ◽  
Long Term Stability

scholarly journals Comparison of the removal of uraemic toxins with medium cut-off and high-flux dialysers: a randomized clinical trial

2019 ◽  
Author(s):  
Mohamed Belmouaz ◽  
Marc Bauwens ◽  
Thierry Hauet ◽  
Valentin Bossard ◽  
Pierre Jamet ◽  
...  
Keyword(s):  
Fibroblast Growth Factor 23 ◽  
High Flux ◽  
Catabolic Rate ◽  
Middle Molecules ◽  
Secondary Endpoints ◽  
Potential Benefits ◽  
To Receive ◽  
And Oxidative Stress ◽  
Protein Catabolic Rate

Abstract Background Accumulation of middle-weight uraemic toxins in haemodialysis (HD) patients results in increased morbidity and mortality. Whether medium cut-off HD (MCO-HD) improves removal of middle-weight uraemic toxins remains to be demonstrated. Methods This cross-over prospective study included 40 patients randomly assigned to receive either 3 months of MCO-HD followed by 3 months of high-flux HD (HF-HD), or vice versa. The primary endpoint was myoglobin reduction ratio (RR) after 3 months of MCO-HD. Secondary endpoints were the effect of MCO-HD on other middle-weight toxins and protein-bound toxins, and on parameters of nutrition, inflammation, anaemia and oxidative stress. Results Compared with HF-HD, MCO-HD provided higher mean RR of myoglobin (36 ± 8 versus 57 ± 13%, P < 0.0001), beta2-microglobulin (68 ± 6 versus 73 ± 15%, P = 0.04), prolactin (32 ± 13 versus 59 ± 11%, P < 0.0001), fibroblast growth factor 23 (20 ± 21 versus 41 ± 22%, P = 0.0002), homocysteine (43 ± 7 versus 46 ± 9%, P = 0.03) and higher median RR of kappa [54 (48–58) versus 70 (63–74)%, P < 0.0001] and lambda free light chain (FLC) [15 (9–22) versus 44 (38–49)%, P < 0.0001]. Mean ± SD pre-dialysis levels of beta2-microglobulin (28.4 ± 5.6 versus 26.9 ± 5.1 mg/L, P = 0.01) and oxidized low-density lipoprote (6.9 ± 4.4 versus 5.5 ± 2.5 pg/mL, P = 0.04), and median (interquartile range) kappa FLC [145 (104–203) versus 129 (109–190) mg/L, P < 0.03] and lambda FLC [106 (77–132) versus 89 (62–125) mg/L, P = 0.002] were significantly lower. Mean albumin levels decreased significantly (38.2 ± 4.1 versus 36.9 ± 4.3 g/L, P = 0.004), without an effect on nutritional status as suggested by unchanged normalized protein catabolic rate and transthyretin level. Conclusions Compared with HF-HD, MCO-HD provides higher myoglobin and other middle molecules RR and is associated with moderate hypoalbuminemia. The potential benefits of this strategy on long-term clinical outcomes deserve further evaluation.

Long-Term Evaluation of the Bonding Strength of Composite Repairs

2012 ◽  
Author(s):  
Khalid Farrag ◽  
Kevin Stutenberg
Keyword(s):  
Shear Strength ◽  
Elevated Temperatures ◽  
Water Solution ◽  
Effect Of Temperature ◽  
Shear Tests ◽  
Composite Repair ◽  
Testing Program ◽  
Repair Systems ◽  
Composite Repairs

The long-term performance of composite repair systems depends on their structural integrity and interaction with the carrier pipe. The adhesives used in the composites are critical components that not only bond the repair to the pipe, but also bond the individual layers of the repair to one another. The durability of the inter-laminate adhesive bond is required to ensure adequate load transfer between the pipe and the composite layers over the predicted lifetime of the repair. A testing program was performed to evaluate the shear strength of the adhesives used in composite repairs. The testing program evaluated the performance of seven commercially-available composite repair systems and it consisted of short-term and long-term shear tests on the adhesives and cathodic disbondment tests on the repair systems. The long-term shear tests were performed for 10,000 hours on samples submerged in a water solution with pH value of 9 and at various loading levels at temperatures of 70°F, 105°F and 140°F. The results of the long-term tests at elevated temperatures were extrapolated to predict the shear strengths at longer durations. The 20-year shear strengths of the composites were estimated using: (a) direct extrapolation of the best-fit curves and (b) the application of the rate process procedure. The results demonstrated the significant effect of temperature on the bond strength of the composites and provided a comparative analysis to evaluate the long-term shear strength and cathodic disbondment of the composite repair systems.

PRESERVATION OF FOSSIL MICROBES AND BIOFILM IN CAVE POOL CARBONATES AND COMPARISON TO OTHER MICROBIAL CARBONATE ENVIRONMENTS

Palaios ◽  
2016 ◽  
Vol 31 (4) ◽  
pp. 177-189 ◽  
Author(s):  
LESLIE A. MELIM ◽  
DIANA E. NORTHUP ◽  
PENELOPE J. BOSTON ◽  
MICHAEL N. SPILDE
Keyword(s):  
Organic Material ◽  
Elevated Temperatures ◽  
Hot Spring ◽  
Cold Seep ◽  
Alternative Mode ◽  
Photolytic Degradation ◽  
Microbial Carbonate ◽  
Edx Analyses ◽  
Uniform Diameter

Abstract Fossil microbes are generally preserved by authigenic minerals, including silica, apatite, iron minerals, clays, and carbonates. An alternative mode of preservation by entombment in calcite, without replacement, has been identified in carbonate cave pool microbialites that were etched and examined in the scanning electron microscope (SEM). Features identified include filaments, threads, and films that show excess carbon in energy dispersive X-ray (EDX) analyses, suggesting preservation of organic matter. Filaments are single smooth or reticulated strands with curving string-like morphology, often hollow, and with a uniform diameter of 0.5 to 1.0 μm. Threads, in contrast, are variable thickness, from several microns down to 0.1 μm, always solid, and commonly branch. Films are thin (< 1 μm) drapes associated with threads. Filaments are interpreted as microbial filaments, while threads and films are interpreted as preserved extracellular polymeric substance (EPS). In addition, microbial filaments and EPS are only revealed via acid etching, suggesting preservation of organic material by entombment, not by replacement with calcite. To determine whether entombed microbes are a common feature of carbonate microbialites that form in different environmental settings, samples of hot spring travertine, caliche soil, and reef microbialite were examined. Whereas the travertine samples were barren, entombed EPS was found in the caliche soil and the reef microbialite; the latter also contained a few entombed filaments. In addition, entombed microbial material has been reported from carbonate cold seep deposits. Such findings indicate that entombment of microbes and EPS in carbonates is not restricted to cave settings, but is more widespread than previously reported. Possible causes for the lack of preservation in travertines include rapid degradation of microbial material either by sunlight due to photolytic degradation, aerobic microbial degradation, detritivore consumption, or elevated temperatures. Rapid carbonate precipitation is ruled out as, somewhat surprisingly, preservation is better in slower growing cave carbonates than in rapidly growing travertines. Potential long-term preservation of organic material entombed in carbonate has implications for the characterization of fossil microbial communities using molecular biomarkers and the search for life on other planets.

scholarly journals Brazing Strategies for High Temperature Ultrasonic Transducers Based on LiNbO3 Piezoelectric Elements

Instruments ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 2 ◽  
Author(s):  
Christopher Bosyj ◽  
Neelesh Bhadwal ◽  
Thomas Coyle ◽  
Anthony Sinclair
Keyword(s):  
High Temperature ◽  
Lithium Niobate ◽  
Elevated Temperatures ◽  
Piezoelectric Element ◽  
Low Noise ◽  
Ultrasonic Transducers ◽  
Acoustic Coupling ◽  
Industrial Operations ◽  
Critical Components

Long-term installation of ultrasonic transducers in high temperature environments allows for continuous monitoring of critical components and processes without the need to halt industrial operations. Transducer designs based on the high-Curie-point piezoelectric material lithium niobate have been shown to both be effective and stable at extreme temperatures for long-term installation. In this study, several brazing techniques are evaluated, all of which aim to provide both mechanical bonding and acoustic coupling directly to a bare lithium niobate piezoelectric element. Two brazing materials—a novel silver-copper braze applied in a reactive air environment and an aluminum-based braze applied in a vacuum environment—are found to be suitable for ultrasound transmission at elevated temperatures. Reliable wide-bandwidth and low-noise ultrasound transmission is achieved between room temperature and 800 °C.

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