scholarly journals Assessment of Bleached and Unbleached Nanofibers from Pistachio Shells for Nanopaper Making

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1371
Author(s):  
Eduardo Robles ◽  
Nagore Izaguirre ◽  
Ander Martin ◽  
Dimitra Moschou ◽  
Jalel Labidi
Keyword(s):  
Viscoelastic Properties ◽  
Uv Spectra ◽  
Polar Component ◽  
Continuous Film ◽  
Water Contact ◽  
Pistachio Shell ◽  
Attractive Option ◽  
Intramolecular Bonding ◽  
Visible Wavelengths ◽  
Lignocellulose Nanofibrils

Cellulose and lignocellulose nanofibrils were extracted from pistachio shells utilizing environmentally friendly pulping and totally chlorine-free bleaching. The extracted nanofibers were used to elaborate nanopaper, a continuous film made by gravimetric entanglement of the nanofibers and hot-pressed to enhance intramolecular bonding. The elaborated nanopapers were analyzed through their mechanical, optical, and surface properties to evaluate the influence of non-cellulosic macromolecules on the final properties of the nanopaper. Results have shown that the presence of lignin augmented the viscoelastic properties of the nanopapers by ≈25% compared with fully bleached nanopaper; moreover, the hydrophobicity of the lignocellulose nanopaper was achieved, as the surface free energy was diminished from 62.65 to 32.45 mNm−1 with an almost non-polar component and a water contact angle of 93.52°. On the other hand, the presence of lignin had an apparent visual effect on the color of the nanopapers, with a ΔE of 51.33 and a ΔL of −44.91, meaning a substantial darkening of the film. However, in terms of ultraviolet transmittance, the presence of lignin resulted in a practically nonexistent transmission in the UV spectra, with low transmittance in the visible wavelengths. In general, the presence of lignin resulted in the enhancement of selected properties which are desirable for packaging materials, which makes pistachio shell nano-lignocellulose an attractive option for this field.

Hydrophobic and UV-resistant properties of environmentally friendly nano-ZnO-coated wood

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Yanan Wang ◽  
Xiaotong Wu ◽  
Yibo Wang ◽  
Yongqi Tian ◽  
Hongbo Mu ◽  
...  
Keyword(s):  
Colour Change ◽  
Environmentally Friendly ◽  
Zno Films ◽  
Zno Film ◽  
Photochromic Properties ◽  
Hydrophobic Properties ◽  
Continuous Film ◽  
Water Contact ◽  
Nano Zno ◽  
Practical Implications

AbstractThe combinations of nano-ZnO with wood through simple and efficient physical methods to prepare environmentally friendly and versatile Nano-ZnO-coated Wood have important research and practical implications. In this paper, an environmentally friendly nano-ZnO-coated wood was prepared by physical magnetron sputtering using Pinus sylvestris L. var. mongholica Litv. The micro-characteristics, structure, wettability and colour change of the ZnO-coated wood were characterized and studied. For samples with a sputtering time of more than 3 min, the surface water contact angle exceeded 130° and had good hydrophobic properties. After a 168 h accelerated ultraviolet (UV) ageing test, the total colour difference (ΔE∗) of the sample with a sputtering time of 75 min (200 °C) was 77% lower than that of the original wood. When the substrate was at 200 °C, the ZnO films deposited on the surface of the wood were evenly and densely arranged, forming almost a continuous film. It could be seen that the deposition of a nano-ZnO film on the surface of wood could significantly improve its hydrophobic properties and anti-UV photochromic properties.

scholarly journals Surface modification of polyamide by 50 Hz dielectric barrier discharge (DBD) produced in air at atmospheric pressure

BIBECHANA ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 19-25
Author(s):  
Rajesh Prakash Guragain ◽  
Hom Bahadur Baniya ◽  
Santosh Dhungana ◽  
Bishnu Prasad Pandey ◽  
Ujjwal Man Joshi ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Dielectric Barrier Discharge ◽  
Atmospheric Pressure ◽  
Barrier Discharge ◽  
Treatment Time ◽  
Industrial Applications ◽  
Polar Component ◽  
Water Contact ◽  
Dielectric Barrier

Industrial applications of the dielectric barrier discharge (DBD) have a long tradition. However, lack of understanding in some of its fundamental issues, such as the stochastic behaviors, is still a challenge for DBD researchers. The work was carried out at line frequency, 15 kV and at atmospheric pressure. This work focuses on the study of the electrical and optical characteristics of DBD at atmospheric pressure to determine a suitable condition for utilization of the device for surface modification of polyamides (PA) (Nylon 6/6). In this work, films were treated by dielectric barrier discharge and the effects on the morphology and chemistry of the material was studied. Surface characteristics were examined via contact angle measurements and SEM. The wettability tests revealed the improvement of the hydrophilic character of the surface of polyamide films as the water contact angle measured after the plasma treatments significantly decreased. The corresponding changes of the total surface energy revealed a significant increase in its polar component. The improvement of the wettability of PA strongly depends on the treatment time. The outcomes of the experiments proved that the modification of surface properties via plasma treatment reach to its saturation point after certain treatment time thus reducing the necessity of further treatment. BIBECHANA 18 (2021) 19-25

scholarly journals Evaluation of the Physical Performance and Working Mechanism of Asphalt Containing a Surfactant Warm Mix Additive

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Jingtao Shi ◽  
Weiyu Fan ◽  
Tihong Wang ◽  
Pinhui Zhao ◽  
Fa Che
Keyword(s):  
Contact Angle ◽  
Spectral Analysis ◽  
Surface Energy ◽  
Asphalt Mixtures ◽  
Polar Component ◽  
Zero Shear Viscosity ◽  
Working Mechanism ◽  
Water Contact ◽  
Temperature Characteristics ◽  
Physical Blending

This paper analyzes the influence of a surfactant warm mix additive on unmodified asphalt’s conventional performance, viscosity-temperature characteristics, surface energy, and spreading performance on aggregate surfaces. The effect of the additive on asphalt’s microstructure was explored by infrared (IR) spectral analysis. The results show the additive has little influence on the penetration, softening point, ductility, and viscosity-temperature characteristics of asphalt; this suggests that the additive does not work by lowering viscosity. The additive can reduce the zero-shear viscosity of asphalt, and adding too much can reduce antirutting performance. The additive also increases the asphalt’s surface energy and the asphalt-water contact angle, while the polar component of surface energy decreases. The additive improves the spreading performance of asphalt on aggregate surfaces and reduces the asphalt-aggregate contact angle; the lower the temperature, the greater the reduction. IR spectral analysis shows that the additive does not react with asphalt—only physical blending occurs. The addition of a surfactant warm mix additive to asphalt allows asphalt mixtures to be more easily mixed and compacted at lower temperatures, thereby saving energy.

Detection and Characterization of earth-like Planets

1997 ◽  
Vol 161 ◽  
pp. 299-311 ◽  
Author(s):  
Jean Marie Mariotti ◽  
Alain Léger ◽  
Bertrand Mennesson ◽  
Marc Ollivier
Keyword(s):  
Direct Detection ◽  
Contrast Ratio ◽  
Angular Size ◽  
Physical Nature ◽  
Major Axis ◽  
Infrared Emission ◽  
Space Technology ◽  
Semi Major Axis ◽  
Earth Like Planets ◽  
Visible Wavelengths

AbstractIndirect methods of detection of exo-planets (by radial velocity, astrometry, occultations,...) have revealed recently the first cases of exo-planets, and will in the near future expand our knowledge of these systems. They will provide statistical informations on the dynamical parameters: semi-major axis, eccentricities, inclinations,... But the physical nature of these planets will remain mostly unknown. Only for the larger ones (exo-Jupiters), an estimate of the mass will be accessible. To characterize in more details Earth-like exo-planets, direct detection (i.e., direct observation of photons from the planet) is required. This is a much more challenging observational program. The exo-planets are extremely faint with respect to their star: the contrast ratio is about 10−10at visible wavelengths. Also the angular size of the apparent orbit is small, typically 0.1 second of arc. While the first point calls for observations in the infrared (where the contrast goes up to 10−7) and with a coronograph, the latter implies using an interferometer. Several space projects combining these techniques have been recently proposed. They aim at surveying a few hundreds of nearby single solar-like stars in search for Earth-like planets, and at performing a low resolution spectroscopic analysis of their infrared emission in order to reveal the presence in the atmosphere of the planet of CO H2O and O3. The latter is a good tracer of the presence of oxygen which could be, like on our Earth, released by biological activity. Although extremely ambitious, these projects could be realized using space technology either already available or in development for others missions. They could be built and launched during the first decades on the next century.

Viscoelastic properties of a bent and straight dimeric liquid crystal

1993 ◽  
Vol 3 (5) ◽  
pp. 597-602 ◽  
Author(s):  
Gregory A. DiLisi ◽  
E. M. Terentjev ◽  
Anselm C. Griffin ◽  
Charles Rosenblatt
Keyword(s):  
Liquid Crystal ◽  
Viscoelastic Properties

The influence of osteopathic correction on the viscoelastic characteristics of the lower leg muscles

2019 ◽  
pp. 93-98
Author(s):  
E. M. Timanin ◽  
N. S. Sydneva ◽  
A. A. Zakharova
Keyword(s):  
Viscoelastic Properties ◽  
Gastrocnemius Muscle ◽  
Soft Tissues ◽  
Subjective Assessment ◽  
Lymphatic Drainage ◽  
Intercellular Substance ◽  
Leg Muscles ◽  
Before And After ◽  
Viscoelastic Characteristics ◽  
Instrumental Methods

Introduction. To date there is a lack of studies dedicated to the objectification of the palpation data obtained by a specialist during the osteopathic examination. The issue of the evidence of the results of osteopathic correction still remains important. Search for instrumental methods allowing to register and to measure various palpation phenomena and manifestations of somatic dysfunctions is very relevant for the development of osteopathy as a science. It is also very important to find objective characteristics of these methods.Goal of research — to study viscoelastic characteristics of the soft tissues of the lower legs by palpation and instrumental methods before and after osteopathic correction.Materials and methods. 22 volunteers (12 women and 10 men) aged 18–23 years without complaints of the musculoskeletal system were examined. Osteopathic diagnostics and measurement of the viscoelastic properties of muscles were carried out by the method of vibration viscoelastometry before and after osteopathic correction.Results. Correlation analysis by Spearman showed that the subjective assessment of an osteopath positively correlated with both elasticity (r=0,43, p<0,05) and viscosity of soft issues (r=0,29, p<0,05). For the gastrocnemius muscle, this pattern was even more pronounced — for elasticity r=0,51, p<0,05, for viscosity =0,34, p<0,05. After osteopathic correction no changes in the elasticity of the soft tissues were observed. The viscosity of the tissues reduced, but in the projection of the gastrocnemius muscle, these changes were not statistically significant (p=0,12), whereas in the projection of the soleus muscle statistically significant changes (p=0,034) were observed.Conclusion. Changes in the viscoelastic properties of tissues demonstrated that the effects of osteopathic correction with the use of myofascial mobilization techniques, articulation mobilization techniques, and lymphatic drainage techniques were not obvious. The elasticity of soft tissues of the lower legs did not change, while the viscosity decreased, especially in the projection of the soleus muscles. This effect of the osteopathic correction can be associated with the effect of thixotropy — the transformation of gel-like intercellular substance into sol. Thus, the research showed that vibration viscoelastometry can be used for the objectifi cation of the condition of soft tissues and of the effects of osteopathic correction.

Nanostructured Polymer Brushes With Reversibly Changing Properties

2002 ◽  
Vol 727 ◽  
Author(s):  
Denys Usov ◽  
Manfred Stamm ◽  
Sergiy Minko ◽  
Christian Froeck ◽  
Andreas Scholl ◽  
...  
Keyword(s):  
Polymer Brushes ◽  
Phase Segregation ◽  
Water Contact ◽  
Angle Measurements ◽  
Nanostructured Polymer ◽  
Contact Angle Measurements ◽  
Vertical Segregation ◽  
Oxygen Plasma Etching ◽  
Grafting From ◽  
Photoemission Electron

AbstractWe investigated the interplay between different mechanisms of the lateral and vertical segregation in the synthesized via “grafting from” approach symmetric A/B (where A and B are poly(styrene-co-2,3,4,5,6-pentafluorostyrene) and poly(methylmethacrylate), respectively) polymer brushes upon exposure to different solvents. We used X-ray photoemission electron spectroscopy and microscopy (X-PEEM), AFM, water contact angle measurements, and oxygen plasma etching to study morphology of the brushes. The ripple morphology after toluene (nonselective solvent) revealed elongated lamellar-like domains of A and B polymers alternating across the surface. The dimple-A morphology consisting of round clusters of the polymer A was observed after acetone (selective solvent for B). The top layer was enriched with the polymer B showing that the brush underwent both the lateral and vertical phase segregation. A qualitative agreement with predictions of SCF theory was found.

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