Use of Interpolation Theory for Determination of The Breaking Load of Blended Yarn

A method for using interpolation theory for determining the breaking load of blended yarn is developed. Lagrangian polynomials are obtained and can be used to predict the breaking load of cotton—Lavsan yarn processed by ring and air spinning methods as a function of the initial properties and percentage content of natural and chemical fibres.     

Cysteine-Encapsulated Liposome for Investigating Biomolecular Interactions at Lipid Membranes

The development of a strategy to investigate interfacial phenomena at lipid membranes is practically useful because most essential biomolecular interactions occur at cell membranes. In this study, a colorimetric method based on cysteine-encapsulated liposomes was examined using gold nanoparticles as a probe to provide a platform to report an enzymatic activity at lipid membranes. The cysteine-encapsulated liposomes were prepared with varying ratios of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and cholesterol through the hydration of lipid films and extrusions in the presence of cysteine. The size, composition, and stability of resulting liposomes were analyzed by scanning electron microscopy (SEM), dynamic light scattering (DLS), nuclear magnetic resonance (NMR) spectroscopy, and UV-vis spectrophotometry. The results showed that the increased cholesterol content improved the stability of liposomes, and the liposomes were formulated with 60 mol % cholesterol for the subsequent experiments. Triton X-100 was tested to disrupt the lipid membranes to release the encapsulated cysteine from the liposomes. Cysteine can induce the aggregation of gold nanoparticles accompanying a color change, and the colorimetric response of gold nanoparticles to the released cysteine was investigated in various media. Except in buffer solutions at around pH 5, the cysteine-encapsulated liposomes showed the color change of gold nanoparticles only after being incubated with Triton X-100. Finally, the cysteine-encapsulated liposomal platform was tested to report the enzymatic activity of phospholipase A₂ that hydrolyzes phospholipids in the membrane. The hydrolysis of phospholipids triggered the release of cysteine from the liposomes, and the released cysteine was successfully detected by monitoring the distinct red-to-blue color change of gold nanoparticles. The presence of phospholipase A₂ was also confirmed by the appearance of a peak around 690 nm in the UV-vis spectra, which is caused by the cysteine-induced aggregation of gold nanoparticles. The results demonstrated that the cysteine-encapsulated liposome has the potential to be used to investigate biological interactions occurring at lipid membranes.     

Effect of the composition of the binder on the mechanical indexes of microplastics made from Lavsan fibre

Impregnation of Lavsan fibres not only increases the strength characteristics and thermal stability of samples of microplastics but also increases the dimensional stability of the fibres on heating. The structural analysis of disorientation of the crystallites in the Lavsan fibres in microplastics shows that increasing the oligourethane acrylate (OUA) content decreases the disorientation of the crystallites, which also explains the course of the shrinkage curves relative to the texture axis. __________ Translated from Khimicheskie Volokna, No. 5, pp. 26–28. September–October, 2007.     

The Ultrafiltration of Very Dilute Colloidal Gold Suspensions

The ultrafiltration behaviour of very dilute colloidal suspensions has been investigated in terms of transmembrane pressure and pH in a batch cell with and without stirring using PM30 and SKIP membranes.For small (10 nm) colloidal gold particles the unstirred flux was higher than the stirred. An increase in concentration polarization due to the lack of stirring shields the electrostatic repulsion between particles, resulting in aggregation of particles that are retained at the membrane surface. This loosely packed layer can be responsible for the higher flux in the unstirred condition. For large (50 nm) gold particles, greater flux was achieved in stirred condition due to the decrease in concentration polarization.While the SKIP membranes showed a complete retention for larger colloidal gold particles, for smaller particles the retention was complete after around 1 minute. The PM30 membrane completely retained colloidal gold particles of both sizes.Lower flux with higher flux decline was obtained for the smaller colloidal gold particles compared to the larger ones. The cross section micrographs show that the larger sol forms a less densely packed deposit layer on the membrane surface. Changing the pH of the colloidal gold suspension resulted in a substantial change to the flux and retention. However the level of local ionic concentration at the membrane surface appears to be of utmost importance as it affects the degree of colloidal aggregation and packing of the deposit layer, thus influencing flux and retention.Analysis of the filtration data coupled with electron microscopy showed that cake filtration was the dominant mechanism during the course of ultrafiltration as well as microfiltration of very dilute colloidal gold suspensions.     

Interaction between Nanoparticles,Membranes and Proteins: A Surface Plasmon Resonance Study

Regardless of the promising use of nanoparticles (NPs) in biomedical applications, several toxic effects have increased the concerns about the safety of these nanomaterials. Although the pathways for NPs toxicity are diverse and dependent upon many parameters such as the nature of the nanoparticle and the biochemical environment, numerous studies have provided evidence that direct contact between NPs and biomolecules or cell membranes leads to cell inactivation or damage and may be a primary mechanism for cytotoxicity. In such a context, this work focused on developing a fast and accurate method to characterize the interaction between NPs, proteins and lipidic membranes by surface plasmon resonance imaging (SPRi) technique. The interaction of gold NPs with mimetic membranes was evaluated by monitoring the variation of reflectivity after several consecutive gold NPs injections on the lipidic membranes prepared on the SPRi biochip. The interaction on the membranes with varied lipidic composition was compared regarding the total surface concentration density of gold NPs adsorbed on them. Then, the interaction of gold and silver NPs with blood proteins was analyzed regarding their kinetic profile of the association/dissociation and dissociation constants (k_off). The surface concentration density on the membrane composed of 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine and cholesterol (POPC/cholesterol) was 2.5 times higher than the value found after the injections of gold NPs on POPC only or with dimethyldioctadecylammonium (POPC/DDAB). Regarding the proteins, gold NPs showed preferential binding to fibrinogen resulting in a value of the variation of reflectivity that was 8 times higher than the value found for the other proteins. Differently, silver NPs showed similar interaction on all the tested proteins but with a variation of reflectivity on immunoglobulin G (IgG) 2 times higher than the value found for the other tested proteins.     

Effect of vibrational actions on stress in synthetic yarns

Conclusions An intense drop in stretching stress which is caused by vibrational action takes place due to the appearance of a residual deformation and of the manifestation of nonlinear viscoelasticity in combination with the known effect of relaxation delay which is realized in half-cycles of deformation reduction.Judging from the measured residual deformations at a deformation level of 2 ± (0.3–0.9)%, in yarn of aromatic polyamide the intensity of loosening in the starting structure which is caused by vibrational action is high and is close to that which takes place under ordinary static mechanical actions.The starting deformation stiffness of Lavsan yarn is more stable with respect to ordinary static loading. Therefore the observable intense loosening in Lavsan yarn under vibrational actions is essentially a vibrational effect.Translated from Khimicheskie Volokna, No. 3, pp. 48–49, May–June, 1984.     

Suppression of gold nanoparticle agglomeration and its separation via nylon membranes

Use of ultraporous nylon membrane is one of the most widely employed techniques for removal of hard and soft nanoparticles in the semiconductor industry,and the accurate determination of membrane pore size is necessary in order to avoid manufacturing defects caused by contamination.The gold nanoparticle has several benefits for the evaluation of polymeric membranes;however,the nanoparticles agglomerate easily on the nylon membrane and make it difficult to evaluate the membrane precisely.The properties of 2-amino-2-hydroxymethyl-1,3-propanediol (ADP) ligand in gold nanoparticle solution were systematically investigated,and ADP was utilized for improved evaluation of the nylon membranes.Nylon membrane used in this study was prepared by phase inversion techniques.Ultrathin dense layer on top of the membrane surface and Darcy structures in the microporous membrane support were observed.The gold particle rejection was carried out at various pH values from 4 to 14 and higher rejection was observed at pH 4 and 8.The suppression of gold colloid agglomeration using ADP and monodispersity of gold colloids was also analyzed by confocal laser scanning microscopy (CLSM),transmission electron microscopy (TEM),and scanning electron microscopy (SEM).van der Waals interaction energy of the particles was reduced in the addition of ADP.The presence ofADP ligand in the gold solutions prevented the agglomeration of gold nanoparticles and reduced the adsorption of the particles on the nylon membrane surface,leading to precise evaluation of membrane pore sizes.     

Computer Modeling of the Product Spun from Chemical and Wool Fibres

The effect of the average length of Lavsan fibres in blending with wool lots with a low average fibre length on the average length and quadratic irregularity of fibres over the length in blended slivers is investigated. Recommendations are made for reducing the irregularity of the blended sliver and improving the conditions in successive transfers—in the combing, roving, and spinning segments of manufacture of worsted yarn.     

Stabilized bismuth oxide–noble metal mixed conducting composites as high temperature oxygen separation membranes

Oxygen concentration cells, with dense dual phase composite membranes made from erbia-stabilized bismuth oxide and a noble metal (Au, Ag), were investigated in the temperature range 650–850°C under controlled oxygen partial pressure gradients. An electrochemical treatment was applied to interpretation of the oxygen permeation data. It is found that the composite membranes exhibit high oxygen permeability relative to the single phase bismuth oxide, since oxygen ions and electrons are allowed to transport through the oxide and metal phase, respectively. The oxygen permeability of the silver-containing composite is at least one order higher than that of the gold-containing one, which can be explained by the fact that silver has a higher catalytic activity than gold for the surface oxygen exchange reaction and thus less limitations are exerted on the overall oxygen transport.     

Water-soluble copolyesters as antistats for Lavsan fibre

Conclusions Water-soluble copolyesters based on ethylene terephthalate, containing more than 25 mole percent of sodium 5-sulfoisophthalate and polyethylene oxide blocks, have an antistatic action with respect to Lavsan fibre.The water-soluble copolyesters synthesized may present interest as brightening or sizing preparations for polyester fibres in textile processing.Translated from Khimicheskie Volokna, No. 3, pp. 19–21, May–June, 1987.     

Recovery of gold from the plating rinse by adsorption with nylon fibers

Taking note of the affinity of some reverse osmosis membranes to Au(CN)^-₂ in the citrate buffered gold plating rinse, we accomplished the recovery of gold by the adsorption to some polymers. Among several polymers, tested nylon fibre had the most excellent characteristics of adsorption. The amount of adsorption of gold on nylon fiber increased with a decrease in pH value of the solution, and 7.5 mg of gold was adsorbed on 1 g of nylon fiber at pH 3, 25°C. The rate of adsorption increased with an increase in temperature. In the case of desorption, the solution containing cyanide ions at a pH as high as 10 was desirable to be employed as an eluant. By passing the simulated plating rinse through a column of nylon fiber, the adsorption and desorption of gold was successfully accomplished. The maximum concentration of gold in the eluant was approximately 600 ppm.     

Complex Metal Cations as Modifiers of the Properties of Polyester Fibres

Treatment of Lavsan fabric with a solution of chromium(III) benzoate complexes causes the highest rate of fixation of acid dye by the fabric and the highest equilibrium sorption, 2.5 times higher than this index for untreated fabric. The fabric also acquires higher capillarity. A simple method is proposed for production of chromium(III) benzoate and salicylate complexes and their composition is investigated spectrophotometrically as a function of the ratio of chromium ions and acid molecules in the solution.     

Polycation stabilization of graphene suspensions

Graphene is a leading contender for the next-generation electronic devices. We report a method to produce graphene membranes in the solution phase using polymeric imidazolium salts as a transferring medium. Graphene membranes were reduced from graphene oxides by hydrazine in the presence of the polyelectrolyte which is found to be a stable and homogeneous dispersion for the resulting graphene in the aqueous solution. A simple device with gold contacts on both sides was fabricated in order to observe the electronic properties.     

Preparation of polyester fibre from polyethylene terephthalate modified with caprolactam

Conclusions A process for preparation of modified Lavsan fibre using caprolactam as the modifier has been proposed and has been checked out on the pilot plant of the Mogilevsk Khimvolokno Industrial Association.The introduction of pentamethylene units into the polyethylene terephthalate macromolecules increases the ability of the fibre to sorb disperse dyes. The modified fibre can be dyed at 100°C without carriers, to a tone of medium intensity.In technological processing of the modified polyester fibre, a decrease in thread defectiveness and breakage in the processes of spinning and weaving is observed. In physico-mechanical indices, the thread and finished semi-wool fabric conform to first grade material.The authors express their thanks to coworkers of the Minsk worsted combine for processing the experimental lot of modified polyester.Translated from Khimicheskie Volokna, No. 3, pp. 37–38, May–June, 1989.     

Gold nanoparticles grown inside carbon nanotubes: synthesis and electrical transport measurements

The hybrid structures composed of gold nanoparticles and carbon nanotubes were prepared using porous alumina membranes as templates. Carbon nanotubes were synthesized inside the pores of these templates by the non-catalytic decomposition of acetylene. The inner cavity of the supported tubes was used as nanoreactors to grow gold particles by impregnation with a gold salt, followed by a calcination-reduction process. The samples were characterized by transmission electron microscopy and X-ray energy dispersion spectroscopy techniques. The resulting hybrid products are mainly encapsulated gold nanoparticles with different shapes and dimensions depending on the concentration of the gold precursor and the impregnation procedure. In order to understand the electronic transport mechanisms in these nanostructures, their conductance was measured as a function of temperature. The samples exhibit a ‘non-metallic’ temperature dependence where the dominant electron transport mechanism is 1D hopping. Depending on the impregnation procedure, the inclusion of gold nanoparticles inside the CNTs can introduce significant changes in the structure of the tubes and the mechanisms for electronic transport. The electrical resistance of these hybrid structures was monitored under different gas atmospheres at ambient pressure. Using this hybrid nanostructures, small amounts of acetylene and hydrogen were detected with an increased sensibility compared with pristine carbon nanotubes. Although the sensitivity of these hybrid nanostructures is rather low compared to alternative sensing elements, their response is remarkably fast under changing gas atmospheres.     

A nucleation and growth study of gold nanowires and nanotubes in polymeric membranes

Through the use of a technique known as template synthesis, it has become possible to synthesize a variety of different materials in the form of nanowires or nanotubes. Dependent upon which type of template is used, either randomly or regularly dispersed nanowires or nanotubes with a wide variety of nanopore diameters and lengths can be created. In this experiment, gold nanowires and nanotubes have been synthesized with diameters of 30, 100, and 800 nm in polycarbonate membranes. The kinetics and characteristics of growth can be greatly altered, dependent upon what operational parameters are employed during deposition. This study looks at the different growth factors that need to be considered when employing the template synthesis approach. These factors include the final expected geometry, the distribution of nucleation sites, the grain size distribution, and the deposition rate.     

Studies on the treatment of gold plating rinse by reverse osmosis

Studies on the treatment of citrate buffered gold plating rinse were carried out with four types of membranes. For three membranes (NS-200, polybenzimidazolone, aromatic polyamide), the rejections of gold were more than 92% in the initial stage of the concentration process, but they decreased remarkably with the increase in the concentration of the feed. For the cellulose acetate membrane, negative rejection was observed as Golomb pointed out. To understand the phenomena more clearly, the relationship between the state of the species in the solution and their permeation behavior was investigated in detail. It was shown that in multiion solutions such as gold plating rinse, a less permeable ion such as the citrate ion improved the permeability of a more permeable ion of like charge such as Au(CN)^-₂. Therefore the recovery of gold was as low as 85% at most in a five-fold concentration of the rinse.     

Orientation stretching of polyester fibre

Conclusions Orientation stretching of Lavsan fibre on twisting-stretching machines takes place in two stages, the ratio between them depending on the temperature conditions in each zone. The thread tenacity depends mainly on the overall stretching frequency, which remains constant over a fairly wide temperature range for a given fibre. The temperature conditions of stretching also determine such fibre properties as the degree of shrinkage and crystallinity.All-Union Scientific-Research Institute for Glass Fibre (VIISV). Translated from Khimicheskie Volokna, No. 6, pp. 13–15, November–December, 1969.     

Preparation of an electrically-conducting yarn based on a mixture of metallized Nitron fibre and Lavsan

Conclusion Laws governing the change in electrical resistance and physicomechanical properties of yarn based on electrically conducting Nitron fibre and Lavsan fibre have been discovered as a function of the ratio of the components in the mixture, the linear density, and the twist coefficient.It has been shown that the change in tenacity at break of the electrically conducting yarn as a function of composition of the mixture does not obey the usual relationships, but has a linear character.Basic equations have been determined which describe the change in yarn properties and permit one to prepare material with assigned characteristics.Translated from Khimicheskie Volokna, No. 2, pp. 19–21, March–April, 1989.     

Reduced graphene oxide–gold nanoparticle membrane for water purification

The reduced graphene oxide–gold nanoparticle (rGO–Au NP) membranes are prepared by vacuum filtration method. The sizes of the Au NPs on the surface of the rGO are about 8–10 nm, and the lattice spacing of Au NPs is 0.0241 nm, which is relative to the cubic lattice of the gold crystal. The layer-by-layer stacking structure of rGO–Au NP membrane can be observed clearly by field emission scanning electron microscopy. The water flux of the rGO–Au NP membrane is as high as 204.1 L m^?2 h^?1 bar^?1, and its retention for Rhodamine B (RhB) is as high as 99.79%.