Assessing colour values of polyester fabrics produced from fibres having different cross-sectional shapes after abrasion

This study assesses the colour, colour difference and colour strength values obtained for eight disperse-dyed polyester fabric samples produced from full and hollow round and trilobal fibres after four sets of abrasion cycle. Each fabric was produced from the same yarns in warp and weft directions. The L *, C *ΔE^*_ab and K/S values of the undyed fabrics and dyed fabrics before and after increasing cycles of abrasion are presented and discussed. Fabrics produced from full and hollow fibres showed great differences regarding colour values in abrasion behaviour. Fabrics produced from hollow fibres were found to be very sensitive to increasing abrasion cycles.     

Effects of microwave irradiation and chemical fixation on the localization of perisinusoidal cells in rat liver by gold impregnation

Modified gold impregnation is one of the methods that are used in light microscopical demonstration of hepatic perisinusoidal cells. This method has some disadvantages, such as restriction of fixation time to 16 h, which allows limited time for processing the tissues, especially when dealing with a large amount of material, and a long impregnation time (16–24 h). We investigated the effect of prolonged fixation on the staining of sections, to shorten the time needed for gold impregnation by using microwave irradiation. Liver specimens were fixed in Baker's calcium–formalin for different periods of time. After fixation, frozen sections were impregnated in gold chloride solution either at room temperature or in a microwave oven. The staining quality of the sections which had been impregnated in the microwave oven for a much shorter time were equal to or even superior to the ones impregnated at room temperature. Prolonging the fixation time up to 7 days did not affect the staining results by microwave irradiation, whereas satisfactory results were not obtained from sections stained at room temperature and fixed for more than 3 days. We conclude that microwave irradiation can be used to shorten the impregnation time in gold chloride solution and the duration of fixation can be prolonged up to 3 days in the original method and up to 7 days when microwave irradiation is used during impregnation.     

Film formation of nano‐sized hard latex (PS) in soft polymer matrix (PBA): An excimer study

This work reports steady state fluorescence (SSF) technique for studying film formation from pyrene (P)‐labeled nano‐sized polystyrene (PS) and poly(n‐butyl acrylate) (PBA) hard/soft latex blends. Blend films were prepared from mixtures of PS and PBA in dispersion. Eight different blend films were prepared in various hard/soft latex compositions at room temperature and annealed at elevated temperatures above glass transition temperature (T_g) of polystyerene. Monomer (I_P) and excimer (I_E) intensities from P was measured after each annealing step to monitor the stages of film formation. The evolution of transparency of latex films was monitored using photon transmission intensity, I_tr. Film morphologies were examined by atomic force microscopy (AFM). The results showed that as the amount of hard component (PS) in the blend is decreased, a significant change occurred in both I_E/I_P and I_tr curves at a certain critical weight fraction (50 wt%) of PS hard latex. Two distinct film formation stages, which are named as void closure and interdiffusion were seen in (I_E/I_P) data above this fraction. However, below 50 wt% PS no film formation was observed. AFM pictures also confirmed these findings. Void closure and interdiffusion stages for (50–100) wt% range of PS were modeled and related activation energies were determined. There was no observable change in activation energies confirming that film formation behavior is not affected by varying the blend composition in this range. POLYM. COMPOS., 31:1611–1619, 2010. © 2009 Society of Plastics Engineers     

Particle size effect on the film‐forming process of PS/PBA composite latexes

In this work, the effect of hard particle size and blend ratio on the film formation behavior of hard polystyrene (PS) and soft poly(n‐butyl acrylate) (PBA) latex blends was studied by means of steady‐state fluorescence and UV–visible techniques in conjunction with atomic force microscopy. Three different sets of latexes were synthesized: PBA latex (diameter 97 nm), pyrene (P)‐labeled large PS (LgPS; diameter 900 nm), and small PS (SmPS; diameter 320 nm). Two different series of latex blends (LgPS/PBA and SmPS/PBA) were prepared with varying blend composition at room temperature separately. Films were then annealed at elevated temperatures above glass transition (T_g) temperature of PS. Fluorescence intensity (I_P) from P and photon transmission intensity (I_tr) were measured after each annealing step to monitor the stages of film formation. The results showed that a significant change occurred in I_P and I_tr at a certain critical weight fraction (R_c) of PBA. Below R_c, two distinct film formation stages, which are named as void closure and interdiffusion, were seen. However, at PBA concentrations nearer to or above R_c, no film formation can be achieved. Comparing to the LgPS/PBA, the sintering process of SmPS/PBA particles occurred at much lower temperatures. Film formation stages for R < R_c were modeled, and related activation energies were calculated. Void closure (ΔH) and interdiffusion (ΔE) activation energies for SmPS/PBA were also found smaller in comparing with LgPS/PBA series. However, ΔH and ΔE values were not changed much with the blend composition for both series. POLYM. COMPOS., 31:1637–1652, 2010. © 2009 Society of Plastics Engineers     

Investigation of the effects of perlite additive on some comfort and acoustical properties of polyester fabrics

Natural perlite material was added for the first time into a polyester filament yarn structure. The water absorption and heat and sound insulation properties of the fabrics produced from textured and twisted polyester yarns containing 1.25% perlite additive were tested, and the results were compared with those obtained on the fabrics produced from reference polyester yarns. Although there are differences between the mechanical properties of the polyester yarns, the yarns including perlite remained within commercial usage limits. The thermal resistance values of polyester sateen fabrics obtained from perlite‐containing yarns were higher than those of the reference fabrics. The contribution of perlite led to a marked improvement, especially in the hydrophilicity and sound insulation of the polyester fabrics. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43128.     

Color‐Temperature Tuning and Control of Trichromatic White Light Emission from a Multisegment ZnCdSSe Heterostructure Nanosheet

Tuning and control of color temperature of trichromatic white light emission is demonstrated for the first time from a single ZnCdSSe nanosheet realized by a novel growth method using chemical vapor deposition (CVD). The nanosheets have thicknesses in the range of 60–350 nm and lateral dimensions of tens of micrometers. These nanosheet structures with three or more parallel segments are able to emit the three primary colors of light from a monolithic body and the combination of the emitted light appears as white. Due to temperature dependence of the alloy composition and the spatial profile of the temperature in the CVD chamber, alloy compositions and the widths of individual segments can be controlled by the substrate locations and the growth time, respectively. Such control determines the emission color and relative intensity of each segment, thus resulting in the tuning of the color temperature of the white light, or in the realization of any visible colors. Trichromatic white light emission is demonstrated with the correlated color temperature covering an extensive range from 2700 to 14 400 K using various growth parameters. In addition, a dynamic tuning of colors and color temperature is demonstrated by sweeping a pump beam across a single nanosheet.     

Enhancing 3G High Speed Wireless Data Performance Through Utilization of 3G–WLAN System Cooperation: A Cross-Network,Cross-Layer Approach

The third generation (3G) wireless networks and wireless local area networks (WLANs) possess complementary characteristics. Recently, there has been significant interest in providing algorithms and specifications that enable their inter-operability. In this paper we propose a novel cross-network, cross-layer algorithm that jointly performs 3G resource allocation and ad-hoc mode WLAN routing towards effectively increasing the performance of the 3G system. The metrics used in this joint design ensures that multi-user diversity is exploited without causing user starvation in the 3G system and the WLAN assistance does not cause an unfair treatment to any of the mobiles from a battery usage point of view. Furthermore, the design attempts to select the WLAN route so that the assistance does not become a major part of the overall link traffic and the internal WLAN traffic can continue almost without any disturbances.     

Spectroscopic study of film formation from polystyrene latex/TiO2 nanocomposites prepared by dip‐coating method

In this study, we investigated the influence of TiO₂ content and thickness of polystyrene (PS) template on film‐formation behavior of PS/TiO₂ composites using fluorescence and ultraviolet–visible techniques in conjunction with scanning electron microscopy. Films were prepared by coating PS templates with various layers of TiO₂ using dip‐coating method. The results showed that PS latexes present complete film formation on top surface of composites. After extraction of PS, a well‐defined interconnected porosity were obtained for thin films when TiO₂ content was increased, whereas thick samples did not present any interconnected porous structures above a certain TiO₂ layer. POLYM. ENG. SCI., 54:288–302, 2014. © 2013 Society of Plastics Engineers     

Fluorescence study of film formation from PS/Al2O3 nanocomposites

Steady state fluorescence (SSF) and UV–vis (UVV) techniques were used to study the film formation behavior of pyrene (P) labeled polystyrene (PS) latex and Al₂O₃ (PS/Al₂O₃) composites depending on PS particles size and Al₂O₃ content. The close-packed arrays of PS spheres (SmPS: 203 nm; LgPS: 382 nm) templates on clean glass substrates were covered with various layers of Al₂O₃ by dip-coating method. Two different film series (SmPS/Al₂O₃ and LgPS/Al₂O₃) were prepared in various Al₂O₃ layer content. The film formation behavior of these composites were studied by annealing them at a temperature range of 100–250 °C and monitoring the scattered light intensity (I_sc), fluorescence intensity (I_P) from P and transmitted light intensity (I_tr) through the films after each annealing step. Optical results indicate that classical latex film formation was occurred for all Al₂O₃ content films and film formation process was unaffected by the Al₂O₃ content for both film series. Extraction of PS template produced highly ordered porous structures for high Al₂O₃ content in both film series. SEM images showed that the pore size and porosity could be easily tailored by varying the PS particle size and the Al₂O₃ content.