Search

The boron-free S700MC steel is usually produced by exploiting the properties of a ferrite-bainite mixed microstructure formed by coiling the strips at a temperature of about 450°C, i.e.below the bainite starting temperature. With the aim of further enhancing the mechanical properties of 6 to 10 mm thick strips, industrial tests were carried out at a coiling temperature of 600°C to promote the formation of a structure of ferrite and carbides, which is also acceptable for this type of steel. Unexpectedly, a microstructure composed of ferrite and martensite was obtained. Compared to the ferritic-bainitic grade, the new structure is characterized by a slight decrease of the yield point but by an increase of the ultimate tensile strength by no less than 80 MPa, with a transition from a quasi-discontinuous to a clearly continuous yielding behaviour. Accordingly, the ratio of yield strength to tensile strength decreases from 0.90 to 0.75 and the impact energy decreases by 35 J and 60 J for the two gauge levels, respectively. The mechanical behaviour of the strips coiled at high temperature is explained as a direct consequence of the dual phase structure with a hard phase interspersed in a soft ferrite matrix. The presence of martensite is explained by the so-called incomplete bainite reaction. The partial transformation into ferrite after coiling and the long time required for the coil to cool down stabilize the untransformed austenite due to the carbon enrichment making bainite formation at lower temperatures impossible.

The hypothesis that one of the primary roles of an effective lubricant is to prevent wear particle agglomeration, thus reduce the plowing of the interfaces by the particles, and lower the frictional force, has been tested through a series of experiments and modeling. The friction coefficient, and the interfacial separation of the sliding surfaces due to entrapped wear particles, were measured on a number of sliding pairs in both dry and lubricated sliding. The results showed that the particle size, even during a single sliding test, did not remain constant but increased as sliding progressed. This increase in the wear particle size was found to be due not to the formation of larger wear particles but to the agglomeration of the small wear particles produced during sliding. The formation of large wear particle agglomerates caused an increase in the amount of plowing and often a concurrent increase in the friction coefficient. When one of the sliding surfaces was textured with undulations, no wear particle agglomeration was observed. The newly formed wear particles simply got entrapped in surface microgrooves and were immediately removed from the sliding interface before their subsequent growth by agglomeration. It was further shown that good' lubricants prevented agglomeration, thus the friction coefficient remained more or less at the initial low value. Both the dry and lubricated sliding test results are presented and discussed in light of the analytical models based on the plastic deformation of the individual wear particles and the slip-line field analysis of the wear particle agglomerate., The study was based on the postulate that lubricants prevent wear particle agglomeration. Experiments were conducted by subjecting various material pairs to sliding in a pin-on-disk apparatus with and without lubricants. Results show that wear debris is not a single particle but an agglomerate of individual wear particles. Lubricants reduce wear particle agglomeration, but only if these are well chosen as not all lubricants are effective.

An online tool based on computational fluid dynamics modelling was developed, validated and applied to Colakoglu Metallurji 2-strands slab caster to monitor and manage steel intermixing in tundish at ladle change. The tool allows to reduce the length of the slabs with intermixed steel. Different tundish layout and operating conditions are accounted for as slab size, presence of flow modifiers in tundish, tundish refill time, casting speed (also different from strand to strand), steel grade. The tool was developed by CSM following the suggestions and needs of Colakoglu Metallurji, who provided to a successful validation of such tool, both with slab sampling and support for installation and testing. As a result, the tool has been integrated into the Colakoglu CC2 control system and is currently used offline for optimizing a priori mixed grade production scheduling, and online for slab cutting optimization in order to reduce the downgraded product amount. [ABSTRACT FROM AUTHOR]

Abstract: Do voters’ assessments of the government's foreign policy performance influence their vote intentions? Does the ‘clarity of responsibility’ in government moderate this relationship? Existing research on the United States demonstrates that the electorate's foreign policy evaluations influence voting behaviour. Whether a similar relationship exists across the advanced democracies in Europe remains understudied, as does the role of domestic political institutions that might generate responsibility diffusion and dampen the effect of foreign policy evaluations on vote choice. Using the attitudinal measures of performance from the 2011 Transatlantic Trends survey collected across 13 European countries, these questions are answered in this study through testing on incumbent vote the diffusion‐inducing effects of five key domestic factors frequently used in the foreign policy analysis literature. Multilevel regression analyses conclude that the electorate's ability to assign punishment decreases at higher levels of responsibility diffusion, allowing policy makers to circumvent the electoral costs of unpopular foreign policy. Specifically, coalition governments, semi‐presidential systems, ideological dispersion among the governing parties and the diverse allocation of the prime ministerial and foreign policy portfolios generate diffusion, dampening the negative effects of foreign policy disapproval on vote choice. This article contributes not only to the debate on the role of foreign policy in electoral politics, but also illustrates the consequential effects of domestic institutions on this relationship. [ABSTRACT FROM AUTHOR]

Valproic acid (VPA) is a drug used for the treatment of epilepsy, bipolar psychiatric disorders, and migraine. Previous studies have reported an increased generation of reactive oxygen species and oxidative stress in the toxic mechanism of VPA. Edaravone, a free radical scavenger for clinical use, can quench free radical reaction by trapping a variety of free radical species. In this study, effect of edaravone on some small intestine biochemical parameters in VPA-induced toxicity was investigated. Thirty seven Sprague Dawley female rats were randomly divided into four groups. The groups include control group, edaravone (30 mg–1 kg–1 day–1) given group, VPA (0.5 g–1 kg–1 day–1) given group, VPA + edaravone (in same dose) given group. Edaravone and VPA were given intraperitoneally for 7 days. Biochemical parameters such as malondialdehyde, as an index of lipid peroxidation(LPO), sialic acid (SA), glutathione levels and glutathione peroxidase, glutathione-S-transferase, superoxide dismutase, catalase, myeloperoxidase, alkaline phosphatase (ALP), and tissue factor (TF) activities were determined in small intestine samples by colorimetric methods. Decreased small intestine antioxidant enzyme activities, increased LPO and SA levels, and increased activities of ALP and TF were detected in the VPA group. Based on our results edaravone may be suggested to reverse the oxidative stress and inflammation due to VPA-induced small intestine toxicity. [ABSTRACT FROM PUBLISHER]

A limited number of studies have investigated in detail the use of drugs during pregnancy. Researchers in the present study investigated the details of drug utilization in pregnant women during the month before pregnancy, at the time that they became aware of the pregnancy, and during the first trimester. Face-to-face interviews were conducted with 359 pregnant women who were admitted to the fetal medicine unit at a university hospital for diagnosis and follow-up. A questionnaire was used to document sociodemographic characteristics and details of drug use. Drugs were categorized according to the US Food and Drug Administration fetal risk classification. Mean maternal age was 29.9+/-5.1 y, and mean gestational age was 19.6+/-9.5 wk. Many of the pregnant women studied (46.6%) were university graduates, and most (61.9%) had a relatively high annual income. Mean gestational age when participants first learned of their pregnancy was 39.8+/-16.4 d. One hundred seventeen participants (32.6%) used drugs during the month before conception, 54 (15%) at the time when they learned of their pregnancy, 180 (50.1%) at the time of the interview, and 289 (80.5%) during the first trimester. The percentages of drugs in categories D and X used by these subjects were 14%, 13.5%, 2.9%, and 5.9%, respectively. Most of the drugs were hormones. The total rate of drug utilization was not high before and during the first trimester of pregnancy. A considerable number of women were using drugs from the D and X categories; however, these numbers decreased significantly when women learned of their pregnancies. Intake of folic acid, vitamins, and iron was very low during the preconception period and was not high enough during the first trimester; this suggests that particular attention should be paid to the use of beneficial "safe" drugs during the preconception and early pregnancy periods. [ABSTRACT FROM AUTHOR]