Solar-flare exposure and thermoluminescence of Luna 24 core material

1980 ◽  
Vol 297 (1428) ◽  
pp. 41-50 ◽  
Keyword(s):  
Solar Flare ◽  
Core Material ◽  
Substantial Fraction ◽  
Natural Radiation ◽  
Mixing Properties ◽  
Local Component ◽  
The Core ◽  
Radiation History ◽  
Solar Flare Tracks ◽  
Over Time

Mineral grains from three depths within the Luna 24 drill core ( ca . 90, 125 and 196 cm) have been examined for solar-flare tracks. Large proportions (55-100%) of grains from all three levels are found to be track-rich (with central track densities p e > 10 8 cm -2 ), and a substantial fraction ( ca . 25-50%) of all grains display trackdensity gradients. These observations indicate that most of the mineral grains have been cycled through the top ca . 1 mm of the lunar surface at some time in their history. Some degree of submaturity is observed towards the bottom of the core. The most likely depositional model envisages rapid infall of highly irradiated material into a less mature local component with rather little subsequent reworking. Thermoluminescence (t.l.) studies indicate a lower natural radiation dose in samples from the 196 cm level compared with those from the two upper levels. This can result either from random variations in the local internal radioactivity or from mixing properties of the pre-irradiated material over time scales of less than ca . 100 ka. Radiation sensitization of samples suggests a possible use of t.l. sensitivity for the interpretation of lunar radiation history.

scholarly journals Acoustic Panels Made of Paper Sludge and Clay Composites

2021 ◽  
Vol 13 (2) ◽  
pp. 637
Author(s):  
Tomas Astrauskas ◽  
Tomas Januševičius ◽  
Raimondas Grubliauskas
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Composite Panel ◽  
Sound Absorption Coefficient ◽  
Core Material ◽  
Paper Sludge ◽  
Frequency Range ◽  
Absorption Properties ◽  
Air Gaps ◽  
The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

scholarly journals Iron Based Core-Shell Structures as Versatile Materials: Magnetic Support and Solid Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 72
Author(s):  
Christian Zambrzycki ◽  
Runbang Shao ◽  
Archismita Misra ◽  
Carsten Streb ◽  
Ulrich Herr ◽  
...  
Keyword(s):  
Water Purification ◽  
Functional Materials ◽  
Core Material ◽  
Solid Catalyst ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
The Core ◽  
Shell Nanostructures ◽  
Sio2 Shell ◽  
Iron Based

Core-shell materials are promising functional materials for fundamental research and industrial application, as their properties can be adapted for specific applications. In particular, particles featuring iron or iron oxide as core material are relevant since they combine magnetic and catalytic properties. The addition of an SiO2 shell around the core particles introduces additional design aspects, such as a pore structure and surface functionalization. Herein, we describe the synthesis and application of iron-based core-shell nanoparticles for two different fields of research that is heterogeneous catalysis and water purification. The iron-based core shell materials were characterized by transmission electron microscopy, as well as N2-physisorption, X-ray diffraction, and vibrating-sample magnetometer measurements in order to correlate their properties with the performance in the target applications. Investigations of these materials in CO2 hydrogenation and water purification show their versatility and applicability in different fields of research and application, after suitable individual functionalization of the core-shell precursor. For design and application of magnetically separable particles, the SiO2 shell is surface-functionalized with an ionic liquid in order to bind water pollutants selectively. The core requires no functionalization, as it provides suitable magnetic properties in the as-made state. For catalytic application in synthesis gas reactions, the SiO2-stabilized core nanoparticles are reductively functionalized to provide the catalytically active metallic iron sites. Therefore, Fe@SiO2 core-shell nanostructures are shown to provide platform materials for various fields of application, after a specific functionalization.

scholarly journals nanocrystals (0 ≤ x ≤ 1): growth, size control and shell formation on β-NaCeF4:Tb core particles

CrystEngComm ◽  
2020 ◽  
Vol 22 (46) ◽  
pp. 8036-8044
Author(s):  
Jannis Wehmeier ◽  
Markus Haase
Keyword(s):  
Size Control ◽  
Lattice Parameters ◽  
Core Material ◽  
Shell Formation ◽  
Shell Material ◽  
Strontium Content ◽  
The Core ◽  
Lighter Lanthanides ◽  
Core Particles

is an interesting shell material for β-NaREF4 particles of the lighter lanthanides (RE = Ce, Pr, Nd), as variation of its strontium content x allows to vary its lattice parameters and match those of the core material.

Equality and Equity in Chinese Higher Education in the Post-massification Era: An Analysis Based on Chinese Scholarly Literature

2021 ◽  
pp. 1-22
Author(s):  
Qiang Zha
Keyword(s):  
Higher Education ◽  
Literature Review ◽  
Bibliometric Analysis ◽  
Chinese Higher Education ◽  
Scholarly Literature ◽  
The Core ◽  
Research Questions ◽  
Changes Over Time ◽  
Core Issues ◽  
Over Time

Abstract This paper examines several research questions relating to equality and equity in Chinese higher education via an extended literature review, which in turn sheds light on evolving scholarly explorations into this theme. First, in the post-massification era, has the Chinese situation of equality and equity in higher education improved or deteriorated since the late 1990s? Second, what are the core issues with respect to equality and equity in Chinese higher education? Third, how have those core issues evolved or changed over time and what does the evolution indicate and entail? Methodologically, this paper uses a bibliometric analysis to detect the topical hotspots in scholarly literature and their changes over time. The study then investigates each of those topical terrains against their temporal contexts in order to gain insights into the core issues.

SHELL MATERIAL'S PERFORMANCE OF THE MICROCAPSULE FOR ELECTROLYTIC CO-DEPOSITION

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3124-3130 ◽  
Author(s):  
HUI CONG LIU ◽  
XIU QING XU ◽  
WEI PING LI ◽  
YAN HONG GUO ◽  
LI-QUN ZHU
Keyword(s):  
Composite Coating ◽  
Methyl Cellulose ◽  
Water Vapor Permeability ◽  
Core Material ◽  
Vapor Permeability ◽  
Shell Material ◽  
The Core ◽  
Surface Performance ◽  
The Stability ◽  
Positive Effect

The shell material of microcapsules has an important effect on the electrolytic co-deposition behavior, the release of core material and the surface performance of composite coating. This paper discussed the tensile property and the stability of three shell materials including polyvinyl alcohol (PVA), gelatin and methyl cellulose (MC). It is found that these three shell materials have good mechanical strength and flexibility which are favorable to electrolytic co-deposition and stability of microcapsules in composite coating and that MC has well permeability and porosity which has a positive effect on the release of the core material in composite coating. Moreover, the study of the thermal properties and water vapor permeability of the three shell materials showed that their permeability improved with increase of temperature and humidity. In addition, the composite copper coating containing microcapsules with PVA, gelatin or MC as shell material was prepared respectively.

scholarly journals What is special about L3 processing?

2013 ◽  
Vol 18 (2) ◽  
pp. 130-144 ◽  
Author(s):  
KEES DE BOT ◽  
CAROL JAENSCH
Keyword(s):  
Second Language ◽  
Language Processing ◽  
Language Use ◽  
Fundamental Question ◽  
Third Language ◽  
The Core ◽  
Dynamic Perspective ◽  
Core Issue ◽  
The Brain ◽  
Over Time

While research on third language (L3) and multilingualism has recently shown remarkable growth, the fundamental question of what makes trilingualism special compared to bilingualism, and indeed monolingualism, continues to be evaded. In this contribution we consider whether there is such a thing as a true monolingual, and if there is a difference between dialects, styles, registers and languages. While linguistic and psycholinguistic studies suggest differences in the processing of a third, compared to the first or second language, neurolinguistic research has shown that generally the same areas of the brain are activated during language use in proficient multilinguals. It is concluded that while from traditional linguistic and psycholinguistic perspectives there are grounds to differentiate monolingual, bilingual and multilingual processing, a more dynamic perspective on language processing in which development over time is the core issue, leads to a questioning of the notion of languages as separate entities in the brain.

Damage behavior of potting materials in sandwich composites with pinned joints

2015 ◽  
Vol 22 (5) ◽  
Author(s):  
Cesim Atas ◽  
Alper Basmaci
Keyword(s):  
Core Material ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Sandwich Composites ◽  
Resin Infusion ◽  
Damage Behavior ◽  
Mechanical Joints ◽  
The Core ◽  
Bottom Face ◽  
Infusion Technique

AbstractThe damage behavior of the potting materials around a pinhole, being used in the mechanical joints of sandwich composites, is investigated experimentally. The sandwich composite panels used in the tests were manufactured by the vacuum-assisted resin infusion technique. Each of the top and bottom face sheets of the panels consisted of two woven E-glass/epoxy layers. As the core material, PVC foam (AIREX

Release Profile of a Model Protein Drug Depending on the Stability of Microspheres Based on Polyelectrolyte Complex

2007 ◽  
Vol 342-343 ◽  
pp. 505-508
Author(s):  
Sung Won Kim ◽  
Yun Sik Nam ◽  
Yeon Jin Min ◽  
Jong Ho Kim ◽  
Kwang Meyong Kim ◽  
...  
Keyword(s):  
Polyelectrolyte Complex ◽  
Coating Layer ◽  
Great Influence ◽  
Release Profile ◽  
Core Material ◽  
Glycol Chitosan ◽  
The Core ◽  
Key Factor ◽  
Model Protein ◽  
The Stability

Stability and disintegration of natural polyelectrolyte complex microspheres for protein drugs delivery have been extensively investigated because of their great influence on the drug release patterns. In this study, we tested stability of microspheres with alginate (Alg) core layered by either chitosan (Chi) or glycol chitosan (GChi) by examining release profiles of fluorophorelabeled bovine serum albumin (BSA) and lysozyme (Lys) from the microspheres. While GChi shell was disintegrated quickly, Chi-shell microspheres showed good stability in PBS. Disintegration of the coated layer induced the core material instable. The results indicated that while the charges of the shell material provided additional diffusion barrier against the protein release, the key factor to hold the proteins inside the microspheres was the integrity of the outer coating layer.

Parameters or cues?

2004 ◽  
Vol 7 (1) ◽  
pp. 35-36 ◽  
Author(s):  
BRIAN MACWHINNEY
Keyword(s):  
Second Language ◽  
Second Language Acquisition ◽  
Language Acquisition ◽  
Hebbian Learning ◽  
Universal Grammar ◽  
Back Propagation ◽  
Parameter Setting ◽  
Functional Categories ◽  
The Core ◽  
Over Time

Truscott and Sharwood Smith (henceforth T&SS) attempt to show how second language acquisition can occur without any learning. In their APT model, change depends only on the tuning of innate principles through the normal course of processing of L2. There are some features of their model that I find attractive. Specifically, their acceptance of the concepts of competition and activation strength brings them in line with standard processing accounts like the Competition Model (Bates and MacWhinney, 1982; MacWhinney, 1987, in press). At the same time, their reliance on parameters as the core constructs guiding learning leaves this model squarely within the framework of Chomsky's theory of Principles and Parameters (P&P). As such, it stipulates that the specific functional categories of Universal Grammar serve as the fundamental guide to both first and second language acquisition. Like other accounts in the P&P framework, this model attempts to view second language acquisition as involving no real learning beyond the deductive process of parameter-setting based on the detection of certain triggers. The specific innovation of the APT model is that changes in activation strength during processing function as the trigger to the setting of parameters. Unlike other P&P models, APT does not set parameters in an absolute fashion, allowing their activation weight to change by the processing of new input over time. The use of the concept of activation in APT is far more restricted than its use in connectionist models that allow for Hebbian learning, self-organizing features maps, or back-propagation.

Injectivity and Propagation of Sulfonated Acrylamide-Based Copolymers in Low Permeability Carbonate Reservoir Cores in Harsh Salinity and Temperature Conditions : Challenges and Learnings from a Middle East Onshore Case Study

2021 ◽  
Author(s):  
Nicolas Gaillard ◽  
Matthieu Olivaud ◽  
Alain Zaitoun ◽  
Mahmoud Ould-Metidji ◽  
Guillaume Dupuis ◽  
...  
Keyword(s):  
Middle East ◽  
Polymer Solutions ◽  
Carbonate Reservoir ◽  
Core Material ◽  
Low Permeability ◽  
The Core ◽  
Reservoir Conditions ◽  
Carbonate Cores ◽  
The Impact ◽  
Mobility Reduction

Abstract Polymer flooding is one of the most mature EOR technology applied successfully in a broad range of reservoir conditions. The last developments made in polymer chemistries allowed pushing the boundaries of applicability towards higher temperature and salinity carbonate reservoirs. Specifically designed sulfonated acrylamide-based copolymers (SPAM) have been proven to be stable for more than one year at 120°C and are the best candidates to comply with Middle East carbonate reservoir conditions. Numerous studies have shown good injectivity and propagation properties of SPAM in carbonate cores with permeabilities ranging from 70 to 150 mD in presence of oil. This study aims at providing new insights on the propagation of SPAM in carbonate reservoir cores having permeabilities ranging between 10 and 40 mD. Polymer screening was performed in the conditions of ADNOC onshore carbonate reservoir using a 260 g/L TDS synthetic formation brine together with oil and core material from the reservoir. All the experiments were performed at residual oil saturation (Sor). The experimental approach aimed at reproducing the transport of the polymer entering the reservoir from the sand face up to a certain depth. Three reservoir coreflood experiments were performed in series at increasing temperatures and decreasing rates to mimic the progression of the polymer in the reservoir with a radial velocity profile. A polymer solution at 2000 ppm was injected in the first core at 100 mL/h and 40°C. Effluents were collected and injected in the second core at 20 mL/h and 70°C. Effluents were collected again and injected in the third core at 4 mL/h and 120°C. A further innovative approach using reservoir minicores (6 mm length disks) was also implemented to screen the impact of different parameters such as Sor, molecular weight and prefiltration step on the injectivity of the polymer solutions. According to minicores data, shearing of the polymer should help to ensure good propagation and avoid pressure build-up at the core inlet. This result was confirmed through an injection in a larger core at Sor and at 120°C. When comparing the injection of sheared and unsheared polymer at the same concentration, core inlet impairment was suppressed with the sheared polymer and the same range of mobility reduction (Rm) was achieved in the internal section of the core although viscosity was lower for the sheared polymer. Such result indicates that shearing is an efficient way to improve injectivity while maximizing the mobility reduction by suppressing the loss of product by filtration/retention at the core inlet. This paper gives new insights concerning SPAM rheology in low permeability carbonate cores. Additionally, it provides an innovative and easier approach for screening polymer solutions to anticipate their propagation in more advanced coreflooding experiments.

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