Influence of the cross‐sectional shape on the structure and properties of polyester fibers

The effects of the fiber cross‐sectional shape on the structure and properties of polyester fibers were investigated. Fully drawn yarn (FDY) polyester fibers (167 dtex and 48 filaments) were produced under the same spinning conditions used in a spinning plant. The only difference between the fibers was their cross‐sectional shapes. Four different cross‐sectional shapes were chosen for the experimental work: round, hollow‐round, trilobal, and hollow‐trilobal. The crystallinity and values of the maximum stress, maximum strain, modulus, yield stress, shrinkage in boiling water, and unevenness of the fibers were determined. The difference in the cross‐sectional shapes influenced the modulus, maximum strain, yield stress, and shrinkage in boiling water. No effects on the crystallinity and maximum stress were observed. The results suggested that the hollow fibers had higher amorphous orientation than the full fibers. The hollow‐round fiber had the highest unevenness value. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2615–2621, 2007     

Casting properties of ASTM A128 Gr. E1 steel modified with Mn-alloying and titanium ladle treatment

This work aims to produce a high manganese steel with more refined austenite grains and better wear resistance without sacrificing the toughness and tensile properties by Mn alloying and Ti ladle treatment in comparision to ASTM A128 Gr. E1 steel (1.0C-13Mn) that is mostly used in the mining industry. The 1.0C-17Mn-xTi alloys (x=0, 0.05 and 0.1, in wt.%) were prepared. A relationship was established between the microstructures and mechanical properties of the as-cast and solution annealed alloys. Increasing Ti content increases the stable Ti(CN) phase on and beside the grain boundaries and decreases up to 37% the austenite grain size of the as-cast alloy with 0.10wt.% Ti. Correspondingly, after solution annealed, optimized titanium content (0.05wt.%) results in significant improvements in wear resistance, hardness, elongation, yield and tensile strengths by 44%, 31%, 30%, 8% and 12%, respectively, except 9% decrease in impact toughness compared to ASTM A 128 Gr. E1 steel without modification. These results show that 1.0C-17Mn-0.05Ti alloy can be used for parts exposed to high load wear and applied in conditions where relatively high tensile properties with sufficent ductility is needed.

     

Ring Opening of Epoxidized Soybean Oil with Compounds Containing Two Different Functional Groups

Epoxidized vegetable oils are desirable chemicals due to their eco‐friendly characteristics and their being a major source of many green products. Ring opening is one of the ways to convert these epoxidized oils to some new intermediates. The use of mono‐functional amines, alcohols, acid anhydrides and thioethers for epoxy ring opening has been reported in the literature. In this study, thioglycolic acid (TGA) bearing thiol and carboxylic acid as two different functional groups and methyl ester of thioglycolic acid (TGAME) were used. Currently, there is no reported literature describing epoxy ring opening using chemicals bearing two different functional groups simultaneously. In this way, two new polyols were synthesized, one with TGA (polyol 1) and one with TGAME (polyol 2). FTIR and ¹H‐ and ¹³C‐NMR spectroscopy confirmed that the ring was opened by the carboxylic acid group of TGA, and the thiol group was not involved in the ring opening whereas the ring was opened by the thiol group in the case of TGAME.     

Co γ-ray irradiation effects on dielectric characteristics of tin oxide films of different thicknesses on n-type Si(1 1 1) substrates

We have tried to determine the effects of ⁶⁰Co gamma irradiation on properties of Au/SnO₂/n-Si (MOS) structures such as dielectric constant (ε′), dielectric loss (ε″), tangent loss (tan δ) and ac conductivity (σ_ac). Three samples were fabricated with different deposition time. The samples were irradiated using a ⁶⁰Co γ-ray source irradiation with the total dose range of 0–500 kGy at room temperature. Capacitance and conductance (C–G–V) measurements were performed at a frequency of 500 kHz in the dark and at room temperature before and after irradiation. The experimental data were analyzed using complex permittivity and electric modulus. The values of ε′, ε″, tan δ and σ_ac showed a strong dependence on the applied voltage and irradiation dose. The dielectric properties of MOS structures have been found to be strongly influenced by the presence of dominant radiation-induced defects. Experimental results show that the interfacial polarization contributes to the improvement of dielectric properties of Au/SnO₂/n-Si (MOS) Schottky diodes.     

The influence of transient thermal loading on the Bree plate; A simplified method of analysis

The paper describes a simplified technique, based upon an extension of the upper bound shakedown theorem, for the evaluation of ratchet boundaries for a plate subject to a through-thickness temperature transient and in-plane loading. The study of a range of cases indicates that transient effects can have a significant effect upon the deformation properties and that strain growth can occur for zero applied loads at quite moderate levels of thermal loading. As a result the identification of transient thermal stresses as F stresses in ASME design codes does not seem acceptable.     

An intutionistic approach based on failure mode and effect analysis for prioritizing corrective and preventive strategies

Although Failure Mode and Effect Analysis (FMEA) is a prominent approach that has been used with convenience as the most popular risk definition and evaluation tool related to a system, a product, or a service, it has several deficiencies. This study addresses these deficiencies and proposes a new intuitionistic approach, which combines FMEA and Weighted Aggregated Sum Product Assessment (WASPAS) by implementing a new intuitionistic scale. Intuitionistic FMEA‐WASPAS can handle uncertainty, vagueness, and hesitancy of the risk evaluation process and provides flexibility for risk assessment. In this study, rankings of corrective‐preventive strategies for failure modes (FMs) are obtained by the proposed approach. To compute Intuitionistic Fuzzy Risk Priority Numbers, occurrence, severity, detection, cost, duration of exposure, and system safety factors are used. A numerical example is also illustrated to present the practicality and effectiveness of the Intuitionistic FMEA‐WASPAS approach.     

Dosimetric analysis of thyroid doses from total cranial irradiation

The purpose was to estimate the radiation dose to the thyroid from total cranial irradiation with parallel opposed lateral fields of 1.25 MeV gamma rays of (60)Co, to represent the current treatment modality, and with 6 MV photon beams derived from a linear accelerator. The mean thyroid doses were measured using thermoluminescence dosemeters in the Rando phantom with two cranial irradiation set-ups: (1) the lateral beams were angled by rotating the collimator to avoid irradiation of the lens and healthy tissues and (2) the lateral beams were not angled, and shielding blocks were used to protect the lens and healthy tissues. For a cranial dose of 18 Gy, thyroid doses for child patients for (60)Co with the open and blocked fields were 0.27 and 0.32 Gy, respectively. With 6 MV, the thyroid dose was less than the doses for (60)Co open and blocked cranial fields by 17 and 10%, respectively. Unblocked cranial fields and a high-energy photon beam should be preferred for cranial irradiation of children.     

Some new binary quasi-cyclic codes from codes over the ring \mathbb F _2+u\mathbb F _2+v\mathbb F _2+uv\mathbb F _2

We consider quasi-cyclic codes over the ring $\mathbb{F }_2+u\mathbb{F }_2+v\mathbb{F }_2+uv\mathbb{F }_2$ , a finite non-chain ring that has been recently studied in coding theory. The Gray images of these codes are shown to be binary quasi-cyclic codes. Using this method we have obtained seventeen new binary quasi-cyclic codes that are new additions to the database of binary quasi-cyclic codes. Moreover, we also obtain a number of binary quasi-cyclic codes with the same parameters as best known binary linear codes that otherwise have more complicated constructions.     

Bioactive Compounds and Antioxidant Activity of Tomato Cultivars

The bioactive compounds of 16 tomato cultivars, grown in the same field for 2 years (2003 and 2004) were investigated. Lycopene (5.7–26.3 mg kg^?1) was the predominant carotenoid, while β-carotene (2.1–11.2 mg kg^?1) and a small amount of lutein (0.02–0.49 mg kg^?1) were found in all tomato cultivars. Kagome 77, the richest source of total carotenoids and L-ascorbic acid, also showed the highest antioxidant activity. β-Carotene and lutein contents of tomatoes differed between 2 years statistically. Antioxidant activities of tomatoes were found between 48 and 118 μmol TEAC 100 g^?1. A significant correlation was only observed between L-ascorbic acid (2.2–13.8 mg 100 g^?1) and antioxidant activity using TEAC assay.     

Experimental Phase Diagram Determination and Thermodynamic Assessment of the CeO2‐Gd2O3‐CoO System

New phase diagram data and a thermodynamic assessment of the CeO‐Gd₂O₃‐CoO system using the CALPHAD approach are presented. This information is needed to understand the surprisingly low sintering temperature (950°C–1050°C) of CeO₂‐based materials doped with small amounts of transition metal oxide (e.g., CoO). Experimental phase equilibria between 1100°C and 1300°C are reported based on the analysis of annealed and molten samples. No isolated compound exists in the ternary. At 1300°C the Co solubility in the ternary compounds Ce_1?x?yGd_xCo_yO_2?x/2?y (fluorite) is 2.7 mol% and is less than 1 mol% in the Gd_2?xCe_xO_3+x/2 (bixbyite). The Ce solubility in the perovskite GdCoO_3?δ was found to be 1 mol%. The lowest temperature eutectic melt in the ternary has a composition of 57.2 mol% Co and 41.1 mol% Gd melting at an onset temperature of 1303 ± 5°C, which is close to the binary eutectic in the Gd₂O₃‐CoO system at 60 ± 2 mol% Co and 1348 ± 1°C.