Anisotropic properties of nanofiber porous materials of fibroin silk and cotton cellulose

2021 ◽  
pp. 2150276
Author(s):  
B. M. Matyakubov ◽  
A. A. Kholmuminov

This paper presents the results of a study on the production of nanofiber anisotropic nanoporous materials based on silk fibroin and cotton cellulose by electrospinning using a rotating screen-receiver of nanofibers in the form of a thin material. The difference in the anisotropic properties of the nanofiber material is shown by the method of birefringence, sorption of water vapor and filtration of a liquid-phase mixture. The possibility of using nanofiber nanoporous fibroin and cotton cellulose materials as a nanofilter of gaseous and liquid-phase mixtures has been shown.

1989 ◽  
Vol 54 (10) ◽  
pp. 2644-2647 ◽  
Author(s):  
Petr Schneider ◽  
Jiří Rathouský

In porous materials filled with water or water solutions of inorganic salts, water freezes at lower temperatures than under normal conditions; the reason is the decrease of water vapor tension above the convex meniscus of liquid in pores. The freezing point depression is not very significant in pores with radii from 0.05 μm to 10 μm (about 0.01-2.5 K). Only in smaller pores, especially when filled with inorganic salt solutions, this depression is important.


Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 189 ◽  
Author(s):  
Sandra Witkiewicz-Lukaszek ◽  
Anna Mrozik ◽  
Vitalii Gorbenko ◽  
Tetiana Zorenko ◽  
Pawel Bilski ◽  
...  

This work is dedicated to the development of new types of composite thermoluminescent (TL) detectors for simultaneous registration of the different components of ionization radiation based on the single crystalline films (SCFs) of Ce3+-doped Lu3−xGdxAl5O12:Ce (x = 0–1.5) garnet and Y3Al5O12:Ce (YAG:Ce) substrates using the liquid phase epitaxy (LPE) growth method. For this purpose, the TL properties of the mentioned epitaxial structures were examined in Risø TL/OSL-DA-20 reader under excitation by α- and β-particles from 242Am and 90Sr-90Y sources. We have shown that the cation engineering of SCF content can result in more significant separation of the TL glow curves of SCFs and substrates under α- and β-particle excitations in comparison with the prototype of such composite detectors based on the Lu3Al5O12:Ce (LuAG:Ce)/YAG:Ce epitaxial structure. Specifically, the difference between the TL glow curves of Lu1.5Gd1.5Al5O12:Ce SCFs and YAG:Ce substrates increases up to 120 K in comparison with a respective value of 80 degrees in the prototype based on the LuAG:Ce/YAG:Ce epitaxial structure. Therefore, the LPE-grown epitaxial structures containing Lu1.5Gd1.5Al5O12:Ce SCFs and Ce3+-doped YAG:Ce substrate can be successfully applied for simultaneous registration of α- and β-particles in mixed fluxes of ionization radiation.


Author(s):  
F Bakhtar ◽  
H Mashmoushy ◽  
O C Jadayel

During the course of expansion of steam in turbines the fluid first supercools and then nucleates to become a two-phase mixture. The liquid phase consists of a large number of extremely small droplets which are difficult to generate except by nucleation. To reproduce turbine two-phase flow conditions requires a supply of supercooled vapour which can be achieved under blow-down conditions by the equipment employed. This paper is the third of a set describing an investigation into the performance of a cascade of rotor tip section profiles in wet steam and presents the results of the wake traverses.


1982 ◽  
Vol 53 (5) ◽  
pp. 1116-1124 ◽  
Author(s):  
R. P. Cole ◽  
P. C. Sukanek ◽  
J. B. Wittenberg ◽  
B. A. Wittenberg

The effect of myoglobin on oxygen consumption and ATP production by isolated rat skeletal muscle mitochondria was studied under steady-state conditions of oxygen supply. A method is presented for the determination of steady-state oxygen consumption in the presence of oxygen-binding proteins. Oxygen consumed in suspensions of mitochondria was replenished continuously by transfer from a flowing gas phase. Liquid-phase oxygen pressure was measured with an oxygen electrode; the gas-phase oxygen concentration was held constant at a series of fixed values. Oxygen consumption was determined from the characteristic response time of the system and the difference in the steady-state gas- and liquid-phase oxygen concentrations. ATP production was determined from the generation of glucose 6-phosphate in the presence of hexokinase. During steady-state mitochondrial oxygen consumption, the oxygen pressure in the liquid phase is enhanced when myoglobin is present. Functional myoglobin present in the solution had no effect on the relation of mitochondrial respiration and ATP production to liquid-phase oxygen pressure. Myoglobin functions in this system to enhance the flux of oxygen into the myoglobin-containing phase. Myoglobin may function in a similar fashion in muscle by increasing oxygen flux into myocytes.


2013 ◽  
Vol 13 (4) ◽  
pp. 10009-10047
Author(s):  
H. H. Aumann ◽  
A. Ruzmaikin

Abstract. Deep Convective Clouds (DCC) have been widely studied because of their association with heavy precipitation and severe weather events. To identify DCC with Atmospheric Infrared Sounder (AIRS) data we use three types of thresholds: (1) thresholds based on the absolute value of an atmospheric window channel brightness temperature; (2) thresholds based on the difference between the brightness temperature in an atmospheric window channel and the brightness temperature centered on a strong water vapor absorption line; and (3) a threshold using the difference between the window channel brightness temperature and the tropopause temperature based on climatology. We find that DCC identified with threshold (2) (referred to as DCCw4) cover 0.16% of the area of the tropical zone and 72% of them are identified as deep convective, 39% are overshooting based on simultaneous observations with the Advanced Microwave Sounding Unit-HSB (AMSU-HSB) 183 GHz water vapor channels. In the past ten years the frequency of occurrence of DCC decreased for the tropical ocean, while it increased for tropical land. The land increase-ocean decrease closely balance, such that the DCC frequency changed at an insignificant rate for the entire tropical zone. This pattern of essentially zero trend for the tropical zone, but opposite land/ocean trends, is consistent with measurements of global precipitation. The changes in frequency of occurrence of the DCC are correlated with the Niño34 index, which defines the SST anomaly in the East-Central Pacific. This is also consistent with patterns seen in global precipitation. This suggests that the observed changes in the frequency are part of a decadal variability characterized by shifts in the main tropical circulation patterns, which does not fully balance in the ten year AIRS data record. The regional correlations and anti-correlations of the DCC frequency anomaly with the Multivariate ENSO Index (MEI) provides a new perspective for the regional analysis of past events, since the SST anomaly in the Nino34 region is available in the form of the extended MEI since 1871. Depending on the selected threshold, the frequency of DCC in the tropical zone ranges from 0.06% to 0.8% of the area. We find that the least frequent, more extreme DCC also show the largest trend in frequency, increasing over land, decreasing over ocean. This finding fits into the framework of how weather extremes respond to climate change.


2008 ◽  
Vol 607 ◽  
pp. 39-41
Author(s):  
Jerzy Kansy ◽  
Radosław Zaleski

A new method of analysis of PALS spectra of porous materials is proposed. The model considers both the thermalization process of positronium inside the pores and the pore size distribution. The new model is fitted to spectra of mesoporous silica MCM-41 and MSF. The resulting parameters are compared with parameters obtained from fitting the “conventional” models, i.e. a sum of exponential components with discrete or/and distributed lifetimes.


2002 ◽  
Vol 110 (1278) ◽  
pp. 118-120 ◽  
Author(s):  
Masaki MAEDA ◽  
Masaya SUZUKI ◽  
Fumihiko OHASHI ◽  
Keiichi INUKAI ◽  
Shinji TOMURA ◽  
...  

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