Processing map for hot working of alpha-zirconium

The hot deformation characteristics of alpha-zirconium in the temperature range of 650°C to 850°C and in the strain-rate range of 10-3 to 102 s-1 are studied with the help of a power dissipation map developed on the basis of the Dynamic Materials Model. The processing map describes the variation of the efficiency of power dissipation (η=2m/m + 1) calculated on the basis of the strain-rate sensitivity parameter (m), which partitions power dissipation between thermal and microstructural means. The processing map reveals a domain of dynamic recrystallization in the range of 730°C to 850°C and 10-2 to 1-1 with its peak efficiency of 40 pct at 800°C and 0.1 s-1 which may be considered as optimum hot-working parameters. The characteristics of dynamic recrystallization are similar to those of static recrystallization regarding the sigmoidal variation of grain size (or hardness) with temperature, although the dynamic recrystallization temperature is much higher. When deformed at 650°C and 10-3 s-1 texture-induced dynamic recovery occurred, while at strain rates higher than 1 s-1, alpha-zirconium exhibits microstructural instabilities in the form of localized shear bands which are to be avoided in processing

Low temperature deformation behaviour of ASTM A-203D nuclear structural steel

The steel A-203D in martensitic, tempered martensitic and ferritic-pearlitic microstructural conditions, was deformed in tension at temperatures between 77 to 300 K and at a strain rate of 6.67×10-5 sec-1. The thermal component of the flow stress and the activation parameters were measured as a function of temperature. It was observed that the microstructure did not affect either the thermal part of the flow stress (σ*) or the activation parameters (V* and ΔH) and that its effect was felt only on the athermal component (σμ) of the flow stress. Further the relations of the activation parameters with stress, strain and temperature were found to be consistent with Dorn-Rajnak theory of Peierls mechanism of plastic deformation. In addition measurements of slow-bend and impact transition were also carried out for ferritic-pearlitic structure. Based on these observations, it is shown that the impact transition temperature of this structure can be emperically correlated with the thermal activation parameters

Investigation of Progress in Dynamic Recrystallization in Two Austenitic Stainless Steels Exhibiting Flow Softening

Abstract The hot working behaviour of two austenitic stainless steels: SS304 and Ti-modified 15Cr-15Ni-2Mo (Alloy D9) were studied by hot compression test at temperatures of 900-1200°C and at strain rates of 0.002-1 s -1 . The progress of dynamic recrystallization (DRX) was modelled by the Avarmi kinetics equation. The flo w softening was directly related to the DRX vo lu me fract ion and the DRX time was determined by strain rate. For quantification of recrystallizat ion rate, the time corresponding to the DRX fraction of 50% was used. Analysis of the sigmoid-shaped recrystallization curves revealed that the rate of DRX increases with increasing deformation temperature and strain rate. Avrami exponents obtained indicated heterogeneous grain or twin boundary nucleation during DRX of these steels. Results of the Avrami analysis were used to predict the DRX flow curves for d ifferent deformation conditions

Teleology and Realism in Leibniz's Philosophy of Science

This paper argues for an interpretation of Leibniz’s claim that physics requires both mechanical and teleological principles as a view regarding the interpretation of physical theories. Granting that Leibniz’s fundamental ontology remains non-physical, or mentalistic, it argues that teleological principles nevertheless ground a realist commitment about mechanical descriptions of phenomena. The empirical results of the new sciences, according to Leibniz, have genuine truth conditions: there is a fact of the matter about the regularities observed in experience. Taking this stance, however, requires bringing non-empirical reasons to bear upon mechanical causal claims. This paper first evaluates extant interpretations of Leibniz’s thesis that there are two realms in physics as describing parallel, self-sufficient sets of laws. It then examines Leibniz’s use of teleological principles to interpret scientific results in the context of his interventions in debates in seventeenth-century kinematic theory, and in the teaching of Copernicanism. Leibniz’s use of the principle of continuity and the principle of simplicity, for instance, reveal an underlying commitment to the truth-aptness, or approximate truth-aptness, of the new natural sciences. The paper concludes with a brief remark on the relation between metaphysics, theology, and physics in Leibniz

Historical inductions, Old and New

I review prominent historical arguments against scientific realism to indicate how they display a systematic overshooting in the conclusions drawn from the historical evidence. The root of the overshooting can be located in some critical, undue presuppositions regarding realism. I will highlight these presuppositions in connection with both Laudan’s ‘Old induction’ and Stanford’s New induction, and then delineate a minimal realist view that does without the problematic presuppositions

Infrastructures of empire: towards a critical geopolitics of media and information studies

The Arab Uprisings of 2011 can be seen as a turning point for media and information studies scholars, many of whom newly discovered the region as a site for theories of digital media and social transformation. This work has argued that digital media technologies fuel or transform political change through new networked publics, new forms of connective action cultivating liberal democratic values. These works have, surprisingly, little to say about the United States and other Western colonial powers’ legacy of occupation, ongoing violence and strategic interests in the region. It is as if the Arab Spring was a vindication for the universal appeal of Western liberal democracy delivered through the gift of the Internet, social media as manifestation of the ‘technologies of freedom’ long promised by Cold War. We propose an alternate trajectory in terms of reorienting discussions of media and information infrastructures as embedded within the resurgence of idealized liberal democratic norms in the wake of the end of the Cold War. We look at the demise of the media and empire debates and ‘the rise of the BRICS’ (Brazil, Russia, India, China, South Africa) as modes of intra-imperial competition that complicate earlier Eurocentric narratives media and empire. We then outline the individual contributions for the special collection of essays

Baidu, Weibo and Renren: The Global Political Economy of Social Media in China

The task of this work is to conduct a global political-economic analysis of China's major social media platforms in the context of transformations of the Chinese economy. It analyses Chinese social media's commodity and capital form. It compares the political economy of Baidu (search engine), Weibo (microblog) and Renren (social networking site) to the political economy of the US platforms Google (search engine), Twitter (microblog) and Facebook (social networking site) in order to analyse differences and commonalities. The comparative analysis focuses on aspects such as profits, the role of advertising, the boards of directors, shareholders, financial market values, terms of use and usage policies. The analysis is framed by the question to which extent China has a capitalist or socialist economy

Updated overall survival from the MONALEESA-3 trial in postmenopausal women with HR+/HER2− advanced breast cancer receiving first-line ribociclib plus fulvestrant

Background The phase III MONALEESA-3 trial included first- (1L) and second-line (2L) patients and demonstrated a significant overall survival (OS) benefit for ribociclib + fulvestrant in patients with hormone receptor–positive, human epidermal growth factor receptor 2–negative (HR+/HER2−) advanced breast cancer (ABC) in the final protocol-specified and exploratory (longer follow-up) OS analyses. At the time of these analyses, the full OS benefit of 1L ribociclib was not completely characterized because the median OS (mOS) was not reached. As CDK4/6 inhibitor (CDK4/6i) + endocrine therapy (ET) is now a preferred option for 1L HR+/HER2− ABC, we report an exploratory analysis (median follow-up, 70.8 months; 14.5 months longer than the prior analysis) to fully elucidate the OS benefit in the MONALEESA-3 1L population. Methods Postmenopausal patients with HR+/HER2− ABC were randomized 2:1 to 1L/2L fulvestrant + ribociclib or placebo. OS in 1L patients (de novo disease or relapse > 12 months from completion of [neo]adjuvant ET) was assessed by Cox proportional hazards model and Kaplan–Meier methods. Progression-free survival 2 (PFS2) and chemotherapy-free survival (CFS) were analyzed. MONALEESA-3 is registered with ClinicalTrials.gov (NCT02422615). Results At data cutoff (January 12, 2022; median follow-up time, 70.8 months), mOS was 67.6 versus 51.8 months with 1L ribociclib versus placebo (hazard ratio (HR) 0.67; 95% CI 0.50–0.90); 16.5% and 8.6% of ribociclib and placebo patients, respectively, were still receiving treatment. PFS2 (HR 0.64) and CFS (HR 0.62) favored ribociclib versus placebo. Among those who discontinued treatment, 16.7% and 35.0% on ribociclib or placebo, respectively, received a subsequent CDK4/6i. No new safety signals were observed. Conclusions This analysis of MONALEESA-3 reports the longest mOS thus far (67.6 months) for 1L patients in a phase III ABC trial. These results in a 1L population show that the OS benefit of ribociclib was maintained through extended follow-up, further supporting its use in HR+/HER2− ABC.This work was supported by Novartis Pharmaceuticals Corporation. The funder of this study, in agreement with the authors and the study steering committee members, designed this study. Representatives of the trial sponsor performed data collection and the subsequent analysis

Corrigendum to ‘Ribociclib plus fulvestrant for postmenopausal women with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer in the phase III randomized MONALEESA-3 trial: updated overall survival’: [Annals of Oncology Volume 32, Issue 8, August 2021, Pages 1015-1024](S0923753421015532)(10.1016/j.annonc.2021.05.353)

peer reviewedThe authors regret that at the time the article was published, Supplementary Table S2 contained errors. This has now been corrected. The authors would like to apologise for any inconvenience caused