Macroscopic ensembles of weakly interacting argon nanoclusters are studied using x-ray diffraction in low vacuum. As the clusters grow by fusion with increasing temperature, their structure ...transforms from essentially face-centered cubic (fcc) to hexagonal close packed as the cluster size approaches ~10(5) atoms. The transformation involves intermediate orthorhombic phases. These data confirm extant theoretical predictions. They also indicate that growth kinetics and spatial constraints might play an important role in the formation of the fcc structure of bulk rare-gas solids, which still remains puzzling.
Cellulose HogC was produced by the modified traditional method with 35% yield from the stem of Sosnovsky hogweed and was characterized by elemental analysis, infrared (IR) spectroscopy, powder X-ray ...diffractometry, differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). For HogC, the degree of crystallinity (approximately 70%) and the glass transition temperature (105–108 °C) were determined. It was found that the whiteness characteristic in the case of HogC was 92% and this significate was obtained without a bleaching procedure using chlorine-containing reagents. In this paper, the possibility of hydrophobization of HogC films by treatment with radiation-synthesized telomers of tetrafluoroethylene is shown. It was found that the contact angle of the telomer-treated cellulose film surface depended on the properties of the telomers (the chemical nature of the solvent, and the initial concentration of tetrafluoroethylene) and could reach 140 degrees.
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•TFE/TMCS telomeres form a defect-free coating on each filament of PET fabric.•TFE/TMHS telomeres provide a water contact angle above 120 degrees on PET fabric.•TFE/TMHS telomeres ...provide uniquely low water absorption of PET fabric.•TFE/TMHS telomeres are highly resistant to intense abrasion effects.•PET fabric with coating based on telomeres TFE/TMHS can "breathe".
The article is devoted to assessing the effectiveness of the hydrophobization effect produced on the polyester fabric by tetrafluoroethylene telomeres obtained by radiation telomerization in trimethylchlorosilane. The indicators of the hydrophobicity of polyester fabrics have been determined and the morphology of the formed coatings has been studied. The dependences of the fabric hydrophobicity on the number of telomeres forming the coatings and the presence of intermediate heat treatment have been investigated. The resistance of coatings based on tetrafluoroethylene telomeres to abrasive effects has been evaluated. It has been found that a polyester fabric with a two- and three-fold coating based on tetrafluoroethylene telomeres synthesized in trimethylchlorosilane has a water contact angle over 120 degrees, very low water absorption, and high resistance to abrasion. Hygienic properties of the fabric do not deteriorate. Such fabric can be used for manufacturing a wide range of household and industrial products.
An analysis from the results of investigation into spatial active damping of pressure fluctuations, vibrations, and vibration forces transferred from power facilities via expansion joints in their ...piping is presented. Vibration transfer from power facilities via piping can be several orders of magnitude greater than along the support structures. This fact should be kept in mind in designing vibration isolation of power equipment from the foundation and the environment through pipelines in the power and transport engineering, shipbuilding, and in oil and gas pipelines in pumping stations. To reduce the transfer of vibrations via a pipeline by means of vibration-isolating expansion joints, it is necessary to decrease their structural stiffness and the forces induced by fluctuations of the working fluid pressure in an expansion joint in a wide frequency band using structural or active methods. A review of the available publications has not revealed, except for the studies performed within the scope of this investigation, any analysis of the interaction between the fluid fluctuations and vibration in the expansion joints or information on reducing the transfer of vibrations and pressure fluctuations via expansion joints in liquid-carrying pipelines. The effectiveness of various multichannel spatial active vibration protection systems whose feedback circuit includes regulators in the form of standard band-pass filters has been studied experimentally. The effect that the interaction of active vibration force damping channels has on the damping efficiency, which may be caused by the cross sensitivity of three-component vibration force sensors during damping of the vibration forces, has been revealed. The active spatial vibration damping of a pipeline downstream of the expansion joint has also demonstrated the interaction of active vibration damping channels resulting in a noticeable change in the damping effectiveness. The effectiveness of the investigated options varied from 10 to 32 dB (reducing fluctuations, transfer of vibration, and forces transmission by 3–30 times) both at individual frequencies and in frequency bands in the range between 10 and 500 Hz.
In this study, variable-temperature grazing-incidence X-ray diffraction, transmission electron and scanning force microscopy were employed to address the semicrystalline structure and surface ...morphology of thin poly(p-xylylene) – silver nanocomposite films with Ag concentrations up to 12 vol.%. It was observed that the dominant crystalline modification of poly(p-xylylene) in the studied films is α-form, which is in contrast to thick poly(p-xylylene) films deposited at liquid nitrogen temperature where β-form prevails. The films exhibit planar texture that can be further enhanced on annealing. The optical properties of the films were studied by UV–vis and IR-spectroscopy. It was found that the samples display surface plasmon resonance, with the peak wavelength in the range of 435–445 nm. The peak positions undergo a redshift upon a long-term storage under ambient conditions. The IR-spectroscopy reveals the bands, which can be assigned to the vibrations of oxygen-containing groups, with intensity increasing with silver content.
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•Thin PPX-Ag nanocomposite films were synthesized by low-temperature VDP.•PPX crystallizes in unusual at such low deposition temperatures α-form.•The films exhibit planar texture that can be further enhanced on annealing.•The samples display surface plasmon resonance with the maximum in the range of 435–445 nm.•The correlation between the structure and optical properties was explored.
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•The results of the study of telomer products obtained during radiation-chemical synthesis are presented.•The molecular structures of all telomers are formed as the spiral chains from ...-(CF2 – CF2)n- which are closed by fragments of telogens molecules.•Acetone, methylene chloride and Freon 113 were used as telogens.•By re-thermal processing of the sample synthesized using acetone as telogen, a new product was obtained.
This work presents the results of a study of tetrafluoroethylene telomers obtained in three types of telogens: acetone, methylene chloride, trichlorotrifluoroethane (Freon 113). The main attention was paid to revealing morphology, molecular structure, phase composition, and thermal properties of the obtained materials. It was revealed that the telomers are formed at using acetone and methylene chloride as telogens and when using trichlorotrifluoroethane, a polymer similar to PTFE is obtained. At heating to 400 °C the telomer obtained when using acetone as telogen, the new product in the form of a white powder was obtained. The obtained product is a tetrafluoroethylene telomer which differs from the initial one in morphology, thermal properties and structure of molecular chains.
The total deep component natural mass discharge Qd (defined in terms of chloride mass discharge Qcl) of the Valley of Geysers, on an average ranges from 280 kg/s from 1961 to 1984, to 230 kg/s after ...2015. Post 2012, discharge measurements reveal a seasonal variation: the discharge increases (340–370 kg/s) during the winter-frozen period, and decreases during the summer flooding period (≈100 kg/s). Long term annually averaged Qd is 274 kg/s, Qcl is 0.247 kg/s and heat flow is 265 MW. In the course of using high-frequency (min−1) observations specific conductance measurements from 2017 to 2020, the total natural discharge was found to be cycling due to the internal cycling of geysers. It was mostly sensitive to the Bolshoy and Velikan geysers with averaged intervals between eruptions of 60 min and 70 min, respectively. The tracer chloride method estimates the volume of hot water erupted from geysers. This method yielded the following estimates: 5–34 m3 of hot water cyclically erupted from the Bolshoy geyser; 0.5–4.5 m3 erupted from the Velikan geyser between 2018 and 2020, and 24–144 m3 erupted before the 2014 mud-flow disaster; and 289–330 m3 erupted from the Grot geyser between May–June 2012. The seasonal features of natural discharge mentioned above may be explained in terms of cold-water infiltration into a two-phase geyser geothermal reservoir, especially if gas-phase condensation induces vacuum conditions, which may further reduce some thermal discharge features.
•High-frequency (min−1) tracer chloride method was used to define Valley of Geysers deep component water natural discharges.•The total Qd significantly decreases during flooding periods, possibly due to cold water inflow into the geyser reservoir.•The tracer chloride method estimates the volumes of hot water erupted from geysers.•Up to 34 m3 (Bolshoy), 144 m3 (Velikan, before the 2014), and 330 m3 (Grot) of hot water have erupted from geysers.
Layer-by-layer assembled shells are prospective candidates for encapsulation, stabilization, storage, and release of fragrances. A shell comprising four alternative layers of a protein and a ...polyphenol is employed to encapsulate the dispersed phase of a fragrance-containing oil-in-water emulsion. The model fragrance used in this work consists of 10 ingredients, covering a range of typically employed aroma molecules, all premixed in equal mass and with sunflower oil acting as the base. The encapsulated emulsion is stable after 2 months of storage at 4 °C as revealed by static light scattering and confocal laser scanning microscopy. Gas chromatography/mass spectrometry data show that the encapsulation efficiency of 8 out of 10 fragrance ingredients depends on the water solubility: the less water-soluble an ingredient, the more of it is encapsulated. The amount of these fragrance ingredients remaining encapsulated decreases linearly upon emulsion incubation at 40 °C and the multilayer shell does not hinder their release. The other two fragrance ingredients having the lowest saturation vapor pressure demonstrate sustained release over 5 days of incubation at 40 °C. The composition of released fragrance remains almost constant over 3 days of incubation, upon further incubation it becomes enriched with these two ingredients when others start to be depleted.
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