Prediction of changing mechanical properties of energetic condensed systems during long-term exploitation by estimation of changing polymeric binder structural properties

This work reports on the incorporation of Flint and Kaolin rocks powders in the cement mortar in an attempt to improve its mechanical properties and produce an eco-friendly mortar. Flint and Kaolin powders are prepared by dry mechanical milling. The two powders are added separately to the mortars substituting cement partially. The two powders are found to improve the mechanical properties of the mortars. Hardness and compressive strength are found to increase with the increase of powders constituents in the cement mortars. In addition, the two powders affect water absorption and thermal conductivity of the mortar specimens which are desirable for construction applications. Kaolin is found to have a greater effect on the mechanical properties, water absorption, and thermal conductivity of the mortars than Flint. This behavior is discussed and analyzed based on the compositional and structural properties of the rocks powders.

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Mechanical Properties of Cement-Treated Soil Mixed with Cellulose Nanofibre

Applied Sciences ◽

10.3390/app11146425 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6425

Author(s):

Hidenori Takahashi ◽

Shinya Omori ◽

Hideyuki Asada ◽

Hirofumi Fukawa ◽

Yusuke Gotoh ◽

...

Keyword(s):

Mechanical Properties ◽

Flexural Strength ◽

Geotechnical Engineering ◽

Strength Development ◽

Soft Ground ◽

Wood Cellulose ◽

Treated Soil ◽

Made In ◽

Cement Treatment

Cellulose nanofibre (CNF), a material composed of ultrafine fibres of wood cellulose fibrillated to nano-order level, is expected to be widely used because of its excellent properties. However, in the field of geotechnical engineering, almost no progress has been made in the development of techniques for using CNFs. The authors have focused on the use of CNF as an additive in cement treatment for soft ground, where cement is added to solidify the ground, because CNF can reduce the problems associated with cement-treated soil. This paper presents the results of a study on the method of mixing CNF, the strength and its variation obtained by adding CNF, and the change in permeability. CNF had the effect of mixing the cement evenly and reducing the variation in the strength of the treated soil. The CNF mixture increased the strength at the initial age but reduced the strength development in the long term. The addition of CNF also increased the flexural strength, although it hardly changed the permeability.

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Dynamical evolution of multiple-population globular clusters

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab223 ◽

2021 ◽

Vol 502 (3) ◽

pp. 4290-4304

Author(s):

Enrico Vesperini ◽

Jongsuk Hong ◽

Mirek Giersz ◽

Arkadiusz Hypki

Keyword(s):

Structural Properties ◽

Globular Clusters ◽

First Generation ◽

Radial Profile ◽

Dynamical Evolution ◽

Evolutionary Phase ◽

Dynamical Parameters ◽

Energy Equipartition

ABSTRACT We have carried out a set of Monte Carlo simulations to study a number of fundamental aspects of the dynamical evolution of multiple stellar populations in globular clusters with different initial masses, fractions of second generation (2G) stars, and structural properties. Our simulations explore and elucidate: (1) the role of early and long-term dynamical processes and stellar escape in the evolution of the fraction of 2G stars and the link between the evolution of the fraction of 2G stars and various dynamical parameters; (2) the link between the fraction of 2G stars inside the cluster and in the population of escaping stars during a cluster’s dynamical evolution; (3) the dynamics of the spatial mixing of the first-generation (1G) and 2G stars and the details of the structural properties of the two populations as they evolve toward mixing; (4) the implications of the initial differences between the spatial distribution of 1G and 2G stars for the evolution of the anisotropy in the velocity distribution and the expected radial profile of the 1G and 2G anisotropy for clusters at different stages of their dynamical history; and (5) the variation of the degree of energy equipartition of the 1G and the 2G populations as a function of the distance from the cluster’s centre and the cluster’s evolutionary phase.

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High-strength and fibrous capsule–resistant zwitterionic elastomers

Science Advances ◽

10.1126/sciadv.abc5442 ◽

2021 ◽

Vol 7 (1) ◽

pp. eabc5442

Author(s):

Dianyu Dong ◽

Caroline Tsao ◽

Hsiang-Chieh Hung ◽

Fanglian Yao ◽

Chenjue Tang ◽

...

Keyword(s):

Mechanical Properties ◽

Mechanical Strength ◽

High Strength ◽

Design Principles ◽

Fibrous Capsule ◽

High Mechanical Strength ◽

Capsule Formation ◽

Locking Mechanism ◽

Fibrous Capsule Formation

The high mechanical strength and long-term resistance to the fibrous capsule formation are two major challenges for implantable materials. Unfortunately, these two distinct properties do not come together and instead compromise each other. Here, we report a unique class of materials by integrating two weak zwitterionic hydrogels into an elastomer-like high-strength pure zwitterionic hydrogel via a “swelling” and “locking” mechanism. These zwitterionic-elastomeric-networked (ZEN) hydrogels are further shown to efficaciously resist the fibrous capsule formation upon implantation in mice for up to 1 year. Such materials with both high mechanical properties and long-term fibrous capsule resistance have never been achieved before. This work not only demonstrates a class of durable and fibrous capsule–resistant materials but also provides design principles for zwitterionic elastomeric hydrogels.

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Effect of Photoinitiator on Precursory Stability and Curing Depth of Thiol-Ene Clickable Gelatin

Polymers ◽

10.3390/polym13111877 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1877

Author(s):

Kai-Hung Yang ◽

Gabriella Lindberg ◽

Bram Soliman ◽

Khoon Lim ◽

Tim Woodfield ◽

...

Keyword(s):

Mechanical Properties ◽

Visible Light ◽

Rheological Properties ◽

Swelling Ratio ◽

Sodium Persulfate ◽

Photo Polymerization ◽

Gelation Kinetics ◽

The Stability ◽

Over Time

Recent advances highlight the potential of photopolymerizable allylated gelatin (GelAGE) as a versatile hydrogel with highly tailorable properties. It is, however, unknown how different photoinitiating system affects the stability, gelation kinetics and curing depth of GelAGE. In this study, sol fraction, mass swelling ratio, mechanical properties, rheological properties, and curing depth were evaluated as a function of time with three photo-initiating systems: Irgacure 2959 (Ig2959; 320–500 nm), lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP; 320–500 nm), and ruthenium/sodium persulfate (Ru/SPS; 400–500 nm). Results demonstrated that GelAGE precursory solutions mixed with either Ig2959 or LAP remained stable over time while the Ru/SPS system enabled the onset of controllable redox polymerization without irradiation during pre-incubation. Photo-polymerization using the Ru/SPS system was significantly faster (<5 s) compared to both Ig2959 (70 s) and LAP (50 s). Plus, The Ru/SPS system was capable of polymerizing a thick construct (8.88 ± 0.94 mm), while Ig2959 (1.62 ± 0.49 mm) initiated hydrogels displayed poor penetration depth with LAP (7.38 ± 2.13 mm) in between. These results thus support the use of the visible light based Ru/SPS photo-initiator for constructs requiring rapid gelation and a good curing depth while Ig2959 or LAP can be applied for photo-polymerization of GelAGE materials requiring long-term incubation prior to application if UV is not a concern.

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Electrospun PCL Patches with Controlled Fiber Morphology and Mechanical Performance for Skin Moisturization via Long-Term Release of Hemp Oil for Atopic Dermatitis

Membranes ◽

10.3390/membranes11010026 ◽

2020 ◽

Vol 11 (1) ◽

pp. 26

Author(s):

Sara Metwally ◽

Daniel P. Ura ◽

Zuzanna J. Krysiak ◽

Łukasz Kaniuk ◽

Piotr K. Szewczyk ◽

...

Keyword(s):

Mechanical Properties ◽

Atopic Dermatitis ◽

Mechanical Performance ◽

Antibacterial Properties ◽

Skin Condition ◽

Fiber Morphology ◽

Suitable Material ◽

Hemp Oil ◽

Skin Moisture

Atopic dermatitis (AD) is a chronic, inflammatory skin condition, caused by wide genetic, environmental, or immunologic factors. AD is very common in children but can occur at any age. The lack of long-term treatments forces the development of new strategies for skin regeneration. Polycaprolactone (PCL) is a well-developed, tissue-compatible biomaterial showing also good mechanical properties. In our study, we designed the electrospun PCL patches with controlled architecture and topography for long-term release in time. Hemp oil shows anti-inflammatory and antibacterial properties, increasing also the skin moisture without clogging the pores. It can be used as an alternative cure for patients that do not respond to traditional treatments. In the study, we tested the mechanical properties of PCL fibers, and the hemp oil spreading together with the release in time measured on skin model and human skin. The PCL membranes are suitable material as patches or bandages, characterized by good mechanical properties and high permeability. Importantly, PCL patches showed release of hemp oil up to 55% within 6 h, increasing also the skin moisture up to 25%. Our results confirmed that electrospun PCL patches are great material as oil carriers indicating a high potential to be used as skin patches for AD skin treatment.

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Evolution of microstructure and mechanical properties of 9Cr ferrite/martensite steels with different Si content after long-term aging at 550 ℃

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2021.159817 ◽

2021 ◽

pp. 159817

Author(s):

Yiyong Zhang ◽

Hao He ◽

Hui Wang ◽

Guang Chen ◽

Xuguang An ◽

...

Keyword(s):

Mechanical Properties ◽

Microstructure And Mechanical Properties ◽

Si Content ◽

Evolution Of Microstructure

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The Effect of Long-Term Impact of Elevated Temperature on Changes in Microstructure and Mechanical Properties of HR3C Steel

Archives of Metallurgy and Materials ◽

10.1515/amm-2016-0129 ◽

2016 ◽

Vol 61 (2) ◽

pp. 761-766 ◽

Cited By ~ 17

Author(s):

A. Zieliński ◽

M. Sroka ◽

A. Hernas ◽

M. Kremzer

Keyword(s):

Mechanical Properties ◽

Elevated Temperature ◽

X Ray ◽

Qualitative And Quantitative ◽

Microstructure And Mechanical Properties ◽

Transmission Electron ◽

Quantitative Identification ◽

Working Parameters ◽

Long Term Impact

Abstract The HR3C is a new steel for pressure components used in the construction of boilers with supercritical working parameters. In the HR3C steel, due to adding Nb and N, the compounds such as MX, CrNbN and M23C6 precipitate during service at elevated temperature, resulting in changes in mechanical properties. This paper presents the results of microstructure investigations after ageing at 650, 700 and 750 °C for 5,000 h. The microstructure investigations were carried out using scanning and transmission electron microscopy. The qualitative and quantitative identification of the existing precipitates was carried out using X-ray analysis of phase composition. The effect elevated temperature on microstructure and mechanical properties of the examined steel was described.

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Polyimide Copolymers Containing Various Levels Of The 6F Moiety For High Temperature And Microelectronic Applications

MRS Proceedings ◽

10.1557/proc-227-35 ◽

1991 ◽

Vol 227 ◽

Cited By ~ 9

Author(s):

M. Haider ◽

E. Chenevey ◽

R. H. Vora ◽

W. Cooper ◽

M. Glick ◽

...

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Electrical Properties ◽

Oxidative Stability ◽

Trifluoromethyl Group ◽

Thermal And Mechanical Properties

ABSTRACTTrifluoromethyl group-containing polyimides not only show extraordinary electrical properties, but they also exhibit excellent long-term thermo-oxidative stability. Among the most thermomechanically stable structural polyimides are those from 6F dianhydride (6FDA) and 6F diamines. The effects of substituting non-fluorine containing monomers such as BTDA, mPDA and 4,4′-DADPS for the hexafluoroisopropylidene monomers on the dielectric, thermo-oxidative, thermal and mechanical properties of the copolymers were studied.

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