scholarly journals On the impact of atmospheric thermal stability on the characteristics of nocturnal downslope flows

1990 ◽  
Vol 51 (1-2) ◽  
pp. 77-97 ◽  
Author(s):  
Z. J. Ye ◽  
J. R. Garratt ◽  
M. Segal ◽  
R. A. Pielke
Keyword(s):  
Thermal Stability ◽  
Downslope Flows ◽  
The Impact

Evaluation of the Impact of Fatty Acid Methyl Ester (FAME) Contamination on the Thermal Stability of Jet A

2013 ◽  
Author(s):  
Jr Morris ◽  
Shardo Robert W. ◽  
Higgins James ◽  
Cook Kim ◽  
Tanner Rhonda ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Fatty Acid ◽  
Methyl Ester ◽  
Fatty Acid Methyl Ester ◽  
Acid Methyl Ester ◽  
Acid Methyl ◽  
The Impact ◽  
Thermal Stability Of

A Novel Gemini Cationic Viscoelastic Surfactant-Based Fluid for High Temperature Well Stimulation Applications

2021 ◽  
Author(s):  
Dawn Friesen ◽  
Brian Seymour ◽  
Aaron Sanders
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Chain Length ◽  
Surfactant Concentration ◽  
Gemini Surfactant ◽  
Alkyl Chain ◽  
Friction Reduction ◽  
Fluid Viscosity ◽  
Viscoelastic Surfactant ◽  
The Impact

Abstract Viscoelastic surfactant (VES)-based fracturing fluids can reduce the risk of formation damage when compared with conventional polymer-based fracturing systems. However, many VES systems lose viscoelasticity rapidly under high-temperature conditions, leading to high fluid leakoff and problems in proppant placement. A gemini cationic VES-based system offering thermal stability above 250°F and its efficiency in friction reduction is presented in this paper. Rheology measurements were conducted on viscoelastic cationic gemini surfactant fluids as a function of temperature (70 – 300°F) and surfactant concentration. The length of surfactant alkyl chain was varied to investigate the impact of surfactant chain length on VES fluid viscosity at elevated temperatures. The effect of flow rate on friction reduction capability of the surfactant fluid was measured on a friction flow loop. Foam rheology measurements were conducted to evaluate the VES fluid's ability to maintain high temperature viscosity with reduced surfactant concentration. A gemini cationic surfactant was used to prepare a viscoelastic surfactant system that could maintain viscosity over 50 cP at a shear rate of 100 s−1up to at least 250°F. With this system, viscoelastic gel viscosity was maintained without degradation for over 18 hours at 250°F, and the fluid showed rapid shear recovery throughout. Decreasing the average alkyl chain length on the surfactant reduced the maximum working temperature of the resulting viscoelastic gel and showed the critical influence of surfactant structure on the resulting fluid performance. The presence of elongated, worm-like micelles in the fluid provided polymer-like friction reduction even at low surfactant concentrations, with friction reduction of over 70% observed during pumping (relative to fresh water) up to a critical Reynolds number. Energized fluids could also be formulated with the gemini surfactant to give foam fluids suitable for hydraulic fracturing or wellbore cleanouts. The resulting viscoelastic surfactant foams had viscosities over 50 cP up to at least 300°F with both nitrogen and carbon dioxide as the gas phase. The information presented in this paper is important for various field applications where thermal stability of the treatment fluid is essential. This will hopefully expand the use of VES-based systems as an alternative to conventional polymer systems in oilfield applications where a less damaging viscosified fluid system is required.

Properties of HDPE/Clay/Wood Nanocomposites

2007 ◽  
Author(s):  
Q. Wu ◽  
Y. Lei ◽  
F. Yao ◽  
Y. Xu ◽  
K. Lian
Keyword(s):  
Thermal Stability ◽  
Tensile Elongation ◽  
Tensile Modulus ◽  
Crystallization Rate ◽  
Clay Content ◽  
Melt Compounding ◽  
Storage And Loss Moduli ◽  
Organic Clay ◽  
The Impact ◽  
Thermal Stability Of

Composites based on high density polyethylene (HDPE), pine flour, and organic clay were made by melt compounding and injection molding. The influence of clay on crystallization behavior, mechanical properties, water absorption, and thermal stability of HDPE/pine composites were investigated. The HDPE/pine composites containing exfoliated clay were made by a two-step melt compounding procedure with a maleated polyethylene (MAPE) as a compatibilizer. Adding 2% clay to a HDPE/pine composite without MAPE decreased the crystallization temperature (Tc) and rate, and the crystallinity level. When 2% MAPE was added, the Tc and crystallization rate increased, but the crystallinity level was lowered. The flexural strength and the tensile strength of HDPE/pine composites increased 19.6% and 24.2% respectively with addition of 1% clay but then decreased slightly as the clay content was increased to 3%. The tensile modulus and tensile elongation were increased 11.8% and 13% respectively with addition of 1% clay but the storage and loss moduli barely change as the clay content was increased to 3%. The impact strength was lowered 7.5% by adding 1% clay, but did not decrease further as more clay was added. The moisture content and thickness swelling of the HDPE/pine composites was reduced by the clay, but did not improve the thermal stability.

The Effects of Oil Palm Fruit Bunch (OPFB) Fiber and Coupling Agent Loadings on the Performance of Hybrid Composites

2012 ◽  
Vol 535-537 ◽  
pp. 154-160 ◽  
Author(s):  
Anizah Kalam ◽  
M.N. Berhan ◽  
Hanafi Ismail
Keyword(s):  
Thermal Stability ◽  
Tensile Strength ◽  
Oil Palm ◽  
Hybrid Composites ◽  
Tensile Modulus ◽  
Palm Fruit ◽  
Degradation Tests ◽  
Mechanical Performances ◽  
The Impact ◽  
Thermal Stability Of

Hybrid composites were prepared by incorporating oil palm fruit bunch (OPFB) fibre in the mixture of clay and polypropylene as secondary filler. OPFB and MAPP loadings were varied to investigate it effects on the performance. Tensile and impact tests were performed on the hybrid composites to evaluate their mechanical performances. Water absorption and thermal degradation tests were also conducted on the hybrid composites. Results indicated that the incorporation of OPFB in PP/PPnanoclay has decreased the thermal stability of hybrid composites. Tensile modulus of hybrid composites increased as the OPFB loading increases and further increased with the increasing of MAPP loading. Generally the tensile strength has decreased with the addition of OPFB, however slight increased was observed when the MAPP loading was increased. The impact strength has also increased with the increasing of OPFB for higher MAPP loading.

scholarly journals Properties of Chemically Modified (Selected Silanes) Lignocellulosic Filler and Its Application in Natural Rubber Biocomposites

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4163 ◽  
Author(s):  
Justyna Miedzianowska ◽  
Marcin Masłowski ◽  
Przemysław Rybiński ◽  
Krzysztof Strzelec
Keyword(s):  
Thermal Stability ◽  
Natural Rubber ◽  
Natural Fibers ◽  
Cereal Straw ◽  
Analysis Technique ◽  
Elastomeric Materials ◽  
Static Mechanical ◽  
Lignocellulosic Filler ◽  
Processing Properties ◽  
The Impact

This article concerns the functional properties of elastomeric composites reinforced with modified lignocellulosic material obtained from cereal straw. The aim of the research was to acquire new knowledge on the effectiveness of cereal straw modification methods in multifunctional properties, while reducing the flammability of newly designed elastomeric materials made of natural rubber. The article deals with investigating and explaining dependencies that affect the performance and processing properties of polymer biocomposites containing modified cereal straw. Three different silanes were used to modify the lignocellulosic filler: n-Propyltriethoxysilane, Vinyltriethoxysilane, and 3,3′-Tetrathiobis(propyl-triethoxysilane). The influence of the conducted modifications on the morphology and structure of straw particles was investigated using a scanning electron microscope, contact angle measurements, and thermogravimetric analysis technique. The increase in hydrophobicity and thermal stability of natural fibers was confirmed. In turn, the impact of silanization on the properties of filled composites was determined on the basis of rheometric characteristics and cross-linking density, static mechanical properties, tear resistance, thermal stability, and flammability tests. Noteworthy was the improvement of the mechanical strength of biocomposites and their resistance to burning. Correlations affecting the structure, morphology, dispersion, and properties of produced composites can facilitate the indication of a further research path in the field of development of new elastomeric biomaterials.

scholarly journals Immune Escape Adaptive Mutations in the H7N9 Avian Influenza Hemagglutinin Protein Increase Virus Replication Fitness and Decrease Pandemic Potential

2020 ◽  
Vol 94 (19) ◽  
Author(s):  
Pengxiang Chang ◽  
Joshua E. Sealy ◽  
Jean-Remy Sadeyen ◽  
Sushant Bhat ◽  
Deimante Lukosaityte ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Avian Influenza ◽  
Virus Replication ◽  
Receptor Binding ◽  
Immune Escape ◽  
Influenza Viruses ◽  
Escape Mutant ◽  
Hemagglutinin Protein ◽  
Ha Protein ◽  
The Impact

ABSTRACT H7N9 avian influenza viruses (AIVs) continue to evolve and remain a huge threat to human health and the poultry industry. Previously, serially passaging the H7N9 A/Anhui/1/2013 virus in the presence of homologous ferret antiserum resulted in immune escape viruses containing amino acid substitutions alanine to threonine at residues 125 (A125T) and 151 (A151T) and leucine to glutamine at residue 217 (L217Q) in the hemagglutinin (HA) protein. These HA mutations have also been found in field isolates in 2019. To investigate the potential threat of serum escape mutant viruses to humans and poultry, the impact of these HA substitutions, either individually or in combination, on receptor binding, pH of fusion, thermal stability, and virus replication were investigated. Our results showed the serum escape mutant formed large plaques in Madin-Darby canine kidney (MDCK) cells and grew robustly in vitro and in ovo. They had a lower pH of fusion and increased thermal stability. Of note, the serum escape mutant completely lost the ability to bind to human-like receptor analogues. Further analysis revealed that N-linked glycosylation, as a result of A125T or A151T substitutions in HA, resulted in reduced receptor-binding avidity toward both human and avian-like receptor analogues, and the A125T+A151T mutations completely abolished human-like receptor binding. The L217Q mutation enhanced the H7N9 acid and thermal stability while the A151T mutation dramatically decreased H7N9 HA thermal stability. To conclude, H7N9 AIVs that contain A125T+A151T+L217Q mutations in the HA protein may pose a reduced pandemic risk but remain a heightened threat for poultry. IMPORTANCE Avian influenza H7N9 viruses have been causing disease outbreaks in poultry and humans. We previously determined that propagation of H7N9 virus in virus-specific antiserum gives rise to mutant viruses carrying mutations A125T+A151T+L217Q in their hemagglutinin protein, enabling the virus to overcome vaccine-induced immunity. As predicted, these immune escape mutations were also observed in the field viruses that likely emerged in the immunized or naturally exposed birds. This study demonstrates that the immune escape mutants also (i) gained greater replication ability in cultured cells and in chicken embryos as well as (ii) increased acid and thermal stability but (iii) lost preferences for binding to human-type receptor while maintaining binding for the avian-like receptor. Therefore, they potentially pose reduced pandemic risk. However, the emergent virus variants containing the indicated mutations remain a significant risk to poultry due to antigenic drift and improved fitness for poultry.

Vinyl-terminated butadiene acrylonitrile improves the toughness, processing window, and thermal stability of bismaleimide resin

2016 ◽  
Vol 29 (10) ◽  
pp. 1199-1208 ◽  
Author(s):  
Dezhi Wang ◽  
Xin Wang ◽  
Lizhu Liu ◽  
Chunyan Qu ◽  
Changwei Liu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Mechanical Performance ◽  
Resin System ◽  
Excellent Performance ◽  
Bismaleimide Resin ◽  
Processing Window ◽  
Low Viscosity ◽  
Isothermal Test ◽  
The Impact ◽  
Thermal Stability Of

Structural materials with excellent toughness, a wide processing window, outstanding mechanical performance, and high thermal stability are highly desired in engineering. This work reports a novel bismaleimide (BMI) resin system fabricated using bis[4-(4-maleimidephen-oxy)phenyl)]propane (BMPP), 1-(2-methyl-5-(2,5-dioxo-2H-pyrrol-1(5 H)-yl) phenyl)-1H-pyrrole-2,5-dione (BTM), and diallyl bisphenol A (DABPA) by a melt method. The behaviors of the BTM/BMPP/DABPA resin were modified by adding vinyl-terminated butadiene acrylonitrile (VTBN) in various amounts. The cured BTM/BMPP/DABPA/VTBN resin system exhibited all of the abovementioned desirable properties. Excellent performance was achieved by the post-cured BMI resin containing 6 phr of VTBN (VTBN-6). The glass transition temperature ( Tg) and the 5% weight loss temperature of VTBN-6 were 278°C and 408°C, respectively. Relative to VTBN-0 (BMI resin without VTBN), the impact strength of cured VTBN-6 (12.32 KJ/m2) improved by 45.6%, and the fracture toughness values, KIC and GIC, increased by 48.7% and 26%, respectively. Moreover, the prepolymer of VTBN-6 exhibited low viscosity over a wide temperature range (70–200°C) under dynamic conditions and for an extended time (70 min; 75% improvement over VTBN-0) in an isothermal test. These results confirm the wide processing window of VTBN-6. The high toughness of the VTBN-containing BMI resin was compatible with other excellent performances of the modified resin.

The impact of calendar aging on the thermal stability of a LiMn2O4–Li(Ni1/3Mn1/3Co1/3)O2/graphite lithium-ion cell

2014 ◽  
Vol 268 ◽  
pp. 315-325 ◽  
Author(s):  
Patrick Röder ◽  
Barbara Stiaszny ◽  
Jörg C. Ziegler ◽  
Nilüfer Baba ◽  
Paul Lagaly ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Lithium Ion ◽  
Lithium Ion Cell ◽  
The Impact ◽  
Thermal Stability Of

Cyclopentadiene: The Impact of Storage Conditions on Thermal Stability

2007 ◽  
Vol 11 (6) ◽  
pp. 1141-1146 ◽  
Author(s):  
David J. am Ende ◽  
David C. Whritenour ◽  
Jotham W. Coe
Keyword(s):  
Thermal Stability ◽  
Storage Conditions ◽  
The Impact

scholarly journals Efficient Preparation and Performance Characterization of the HMX/F2602 Microspheres by One-Step Granulation Process

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Conghua Hou ◽  
Xinlei Jia ◽  
Jingyu Wang ◽  
Yingxin Tan ◽  
Yuanping Zhang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Stability ◽  
Particle Size ◽  
Particle Morphology ◽  
Xrd Analysis ◽  
Impact Sensitivity ◽  
Scanning Calorimetry ◽  
Granulation Process ◽  
One Step ◽  
The Impact

A new one-step granulation process for preparing high melting explosive- (HMX-) based PBX was developed. HMX/F2602 microspheres were successfully prepared by using HMX and F2602 as the main explosive and binder, respectively. The particle morphology, particle size, crystal structure, thermal stability, and impact sensitivity of the as-prepared HMX/F2602 microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer, differential scanning calorimetry (DSC), and impact sensitivity test, respectively. The SEM analysis indicated successful coating of F2602 on the surface of HMX, and the resulting particles are ellipsoidal or spherical with a median particle size of 940 nm; the XRD analysis did not show any change in the crystal structure after the coating and still has β-HNX crystal structure; according to the DSC analysis, HMX/F2602 prepared by the new method has better thermal stability compared to that prepared by the water suspension process. The impact sensitivity of HMX/F2602 prepared by this one-step granulation process decreased, and its characteristic height H50 increased from 37.62 to 40.13 cm, thus significantly improving the safety performance. More importantly, this method does not need the freeze-drying process after recrystallization, thus increasing the efficiency by 2 to 3 times.

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