In situ study of fiber structure development of poly(butylene terephthalate) in a continuous laser-heated drawing process

The structural development of poly(butylene terephthalate) (PBT) fibers was analyzed using in situ wide angle X-ray diffraction and fiber temperature measurements during CO2 laser-heated drawing, in which the necking position on the running fiber could be fixed by CO2 laser irradiation. The measured parameters were determined as functions of the elapsed time after necking with a time resolution of 0.3 ms. The as-spun PBT fibers, which exhibited a low-oriented alpha-crystalline structure, were drawn to a draw ratio of 5 using laser heating. The (001') reflection, which indicates a quasi-smectic fibrillar structure, was not observed before crystallization in contrast to measurements of poly(ethylene terephthalate) (PET) and poly(ethylene 2,6-naphthalene dicarboxylate) (PEN). The alpha-crystal was transformed into an oriented beta-form crystal at the necking position, and the developed beta-crystallites exhibited increased size and altered orientation <2 ms after necking. The fiber temperature increased rapidly at around T-g, and the rearrangement of the beta-crystal primarily occurred as the fiber's temperature rose from 100 to 160 degrees C. The oriented beta-crystal of the drawn fiber transformed into the oriented beta-crystal when the drawing tension was released. Polymer Journal (2012) 44, 1030-1035; doi: 10.1038/pj.2012.65; published online 18 April 2012ArticlePOLYMER JOURNAL. 44(10):1030-1035 (2012)journal articl

Fiber structure development in PS/PET sea-island conjugated fiber during continuous laser drawing

The effect of draw ratio, molecular weight, and sea-island conjugated spinning with a polystyrene component on the fiber structure development of PET during laser drawing was analyzed by in-situ measurements with a 0.1 ms time resolution using an ultra-high luminance X-ray beam generated from a synchrotron equipped with an undulator. The fiber temperature increased from 120 °C to 160–220 °C during the structure development process. By drawing the higher molecular weight PET to a higher draw ratio, a larger amount of fibrillar smectic mesophase formed just after the onset of necking, and a more highly oriented crystal formed after the extinction of the smectic mesophase. Accordingly, fibers with higher strength and higher thermal shrinkage stress were obtained. On the other hand, by conjugated spinning with a PS component, the fiber temperature increased along with an increase in the drawing stress, but the stress applied to the PET component should have decreased. The amount of smectic mesophase formed by the conjugated-spinning process was drastically decreased, and no crystallization induction time was observed, unlike the other cases. Crystallization, particularly the growth of a lamellar crystal, was also promoted. Moreover, a higher Young's modulus, a higher yield stress, and a higher shrinkage stress were observed for the conjugated-spun and drawn fibers. Therefore, the fibrillar smectic mesophase seems to block the formation of the lamellar crystal. Furthermore, the resultant fibrillar structure tends to result in a higher strength, but a relatively lower modulus and yield strength of the fiber.ArticlePOLYMER. 79:37-46 (2015)journal articl

Novel pre-treatment method for seawater reverse osmosis: Fibre media filtration

A high rate fibre filter was used as a pre-treatment to seawater reverse osmosis (SWRO) to reduce membrane fouling. Seawater was drawn from Chowder Bay where the Sydney Institute of Marine Science, Australia is located. A lab-scale fibre filter with a height of 1000 mm and a diameter of 30 mm was used in conjunction with in-line coagulation. The effect of operating the fibre filter with different packing densities (105, 115 kg/m3) and filtration velocities (40, 60 m/h) was investigated in terms of silt density index (SDI10), modified fouling index (MFI), pressure drop (ΔP), turbidity and molecular weight distribution (MWD). The use of in-line coagulation improved the performance of fibre filter as measured by the MFI and SDI. Regardless of filtration velocity and packing density the MFI and SDI10 values remained low as did the turbidity until the end of the filtration run. The MWD analysis showed the removal efficiencies of organic materials like biopolymers, fulvic acids, low MW acids for even experiments with the highest filtration velocity (60 m/h) and lowest packing density (105 kg/m3). This pre-treatment has a small foot print as it has the capacity of operating at a very high filtration velocity. © 2009 Elsevier B.V. All rights reserved

Effects of surgical side and site on mood and behavior outcome in children with pharmacoresistant epilepsy

Children with epilepsy have a high rate of mood and behavior problems; yet few studies consider the emotional and behavioral impact of surgery. No study to date has been sufficiently powered to investigate effects of both side (left/right) and site (temporal/frontal) of surgery. One hundred patients (aged 6-16) and their families completed measures of depression, anxiety, and behavioral function as part of neuropsychological evaluations before and after surgery for pharmacoresistant epilepsy. Among children who had left-sided surgeries (frontal = 16; temporal = 38), there were significant interactions between time (pre to post-operative neuropsychological assessment) and resection site (frontal/temporal) on anhedonia, social anxiety, and withdrawn/depressed scales. Patients with frontal lobe epilepsy (FLE) endorsed greater pre-surgical anhedonia and social anxiety than patients with temporal lobe epilepsy (TLE) with scores normalizing following surgery. While scores on the withdrawn/depressed scale were similar between groups before surgery, the FLE group showed greater symptom improvement after surgery. In children who underwent right-sided surgeries (FLE = 20; TLE = 26), main effects of time (patients in both groups improved) and resection site (caregivers of FLE patients endorsed greater symptoms than those with TLE) were observed primarily on behavior scales. Individual data revealed that a greater proportion of children with left FLE demonstrated clinically significant improvements in anhedonia, social anxiety, and aggressive behavior than children with TLE. This is the first study to demonstrate differential effects of both side and site of surgery in children with epilepsy at group and individual levels. Results suggest that children with FLE have greater emotional and behavioral dysfunction before surgery, but show marked improvement after surgery. Overall, most children had good emotional and behavioral outcomes, with most scores remaining stable or improving. © 2014 Andresen, Ramirez, Kim, Dorfman, Haut, Klaas, Jehi, Shea, Bingaman and Busch

Observation of micro-scale surface morphology with microtexture development during plane strain tensile deformation in AZ31 magnesium alloy

The change of microstructure including microtexture and surface morphology in AZ31 magnesium alloy under plane strain tension was investigated by 3D observation combined confocal microscope and high-resolution electron backscattered diffraction. Micro-scale changes in the surface morphology were observed on the area including tensile twin bands. The mechanism for surface morphology variation was discussed with the nucleation of tensile twinning and the strain partitioning caused by continuing deformation after the nucleation of the twins.open1111sciescopu

Measuring the deviation of the 2-3 lepton mixing from maximal with atmospheric neutrinos

The measurement of the deviation of the 2-3 leptonic mixing from maximal, D_23 = 1/2 - sin^2(theta_23), is one of the key issues for understanding the origin of the neutrino masses and mixing. In the three-neutrino context we study the dependence of various observables in the atmospheric neutrinos on D_23. We perform a global three-neutrino analysis of the atmospheric and reactor neutrino data taking into account the effects of both the oscillations driven by the "solar" parameters (Delta_m_21^2 and theta_12) and the 1-3 mixing. The departure from the one-dominant mass scale approximation results into the shift of the 2-3 mixing from maximal by Delta_sin^2(theta_23) ~ 0.04, so that D_23 ~ 0.04 +- 0.07 (1 sigma). Though value of the shift is not statistically significant, the tendency is robust. The shift is induced by the excess of the e-like events in the sub-GeV sample. We show that future large scale water Cherenkov detectors can determine D_23 with accuracy of a few percent, comparable with the sensitivity of future long baseline experiments. Moreover, the atmospheric neutrinos will provide unique information on the sign of the deviation (octant of theta_23).Comment: 20 pages, LaTeX2e file using RevTEX4, 6 figures and 1 table include

Social media use and impact during the holiday travel planning process

Through an empirical study among holiday travellers, residing in the Former Soviet Union Republics, this paper presents a comprehensive view of role and impact of social media on the whole holiday travel planning process: Before, during and after the trip, providing insights on usage levels, scope of use, level of influence and trust. Findings suggest that social media are predominantly used after holidays for experience sharing. It is also shown that there is a strong correlation between perceived level of influence from social media and changes made in holiday plans prior to final decisions. Moreover, it is revealed that user-generated content is perceived as more trustworthy when compared to official tourism websites, travel agents and mass media advertising

Significant associations of PAI-1 genetic polymorphisms with osteonecrosis of the femoral head

<p>Abstract</p> <p>Background</p> <p>The pathogenesis of osteonecrosis of the femoral head (ONFH) has been implicated in hypofibrinolysis and blood supply interruption. Previous studies have demonstrated that decreased fibrinolytic activity due to elevated plasminogen activator inhibitor-1 (PAI-1) levels correlates with ONFH pathogenesis. The -675 4G/5G single nucleotide polymorphism (SNP rs1799889) in the PAI-1 gene promoter is associated with PAI-1 plasma level. We investigated whether rs1799889 and two other SNPs of the PAI-1 gene (rs2227631, -844 G/A in the promoter; rs11178, +10700 C/T in the 3'UTR) are associated with increased ONFH risk.</p> <p>Methods</p> <p>Three SNPs in PAI-1 were genotyped in 206 ONFH patients and 251 control subjects, using direct sequencing and a TaqMan^®5' allelic discrimination assay. We performed association analysis for genotyped SNPs and haplotypes with ONFH.</p> <p>Results</p> <p>The 4G allele of rs1799889, A allele of rs2227631, and C allele of rs11178 were significantly associated with increased ONFH risk (p = 0.03, p = 0.003, and p = 0.002, respectively). When we divided the population according to gender, an association between the three SNPs and increased risk of ONFH was found only in men. In another subgroup analysis based on the etiology of ONFH, rs2227631 (A allele) and rs11178 (C allele) in the idiopathic subgroup (p = 0.007 and p = 0.021) and rs1799889 (4G allele) and rs11178 (C allele) in the alcohol-induced subgroup (p = 0.042 and p = 0.015) were associated with increased risk of ONFH. In addition, a certain haplotype (A-4G-C) of PAI-1 was also significantly associated with ONFH (p < 0.001).</p> <p>Conclusion</p> <p>Our findings demonstrated that three SNPs (rs1799889, rs2227631, and rs11178) of the PAI-1 gene were associated with ONFH risk. This study also suggests that PAI-1 SNPs may play an important role in ONFH.</p