Search

One task of historians is to construct causal ascription of singular historicals between eminent historical events. For instance, the controversy resulting from the confusing butterfly ballot of Florida’s year 2000 presidential election cost Gore his presidency. However, to research into these matters is inevitably to appeal to counterfactual deliberation in an epistemic fashion because the past is fixed. One standard idea is Max Weber’s, Weber causation: “f was a cause of φ” is assertable iff “¬f □→ ¬φ” is assertable. Reiss (2009) gives an exceptionally good analysis of this topic and outlines historians’ reasoning, claiming that backtracking analyses of counterfactual conditionals employed in historical thought experiments is the signature of historical study of causal ascription of singular historicals. Nevertheless, he concludes that it is very difficult to reach an uncontroversial ascription for this sort in most cases. For this reason, he proposes to find difference-making relations that will suffice. The objective of this paper is to provide a more fine-grained, intervention-based, backtracking analysis of counterfactual conditionals upon which a more satisfactory account of causal ascription of singular historicals can be given. Reiss’ account of difference-making relation will be shown to be unsatisfactory. Moreover, a formal ground of the epistemology of historical thought experiments can be given, along with the constraints of this account resultant from the semantic features of non-transitivity and strong centering of counterfactual conditionals. Finally, some epistemological points of causal ascription of singular historicals and historical thought experiments will be given.

The study describes the recoverable strain in Ti-24Nb-4Zr-8Sn (wt.%) alloy with cellular structure having rhombic dodecahedron and topology-optimised unit cell fabricated by electron beam melting. ...

We explore the treatment of bone metastases in advanced non-small cell lung cancer (NSCLC).We reported a 76-year-old female patient, who was diagnosed with NSCLC with bone metastasis eight years ago (stage IVA). Due to unbearable diarrhea, she refused chemotherapy, and we adopted local treatment, including local radiotherapy 50 Gy and bone cement to lumbar spinal metastases, 62 Gy local radiotherapy of primary lung tumor, TKI inhibitor gefitinib and zoledronic acid.She survived more than eight years and is still in follow-up.The median survival time for NSCLC patients with bone metastases is often less than 1 year. We reported the patient with more than eight years of survival, showed that some special cases can adopt the methods of local treatment including bone cement, treatment benefit patients, radiation therapy and targeted therapy in clinic to expand the survival.

In the era of precision medicine, molecular and genetic biomarkers act as the key indicators for glioma patients' recurrence and prognosis.We summarize the biomarkers of glioma prognosis from molecular level, gene level and microRNA level.In molecular biomarkers, cyclinD1 high expression/P16 low expression, MIF high expression and VEGF high expression were all related to glioma patients' poor prognosis; in genetic biomarkers, MGMT promoter methylation absence, IDH1 wild type, HIF-α high expression, Chromosome 1p/19q non-deletion and TERT promoter mutation were associated with poor prognosis for glioma; in microRNA biomarkers, miR-524-5p, miR-586, miR-433, miR-619, miR-548d-5p, miR-525-5p, miR-301a, miR-210, miR-10b-5p, miR-15b-5p and miRNA-182 high expression, miR-124, miR-128, miR-146b and miR-218 low expression were commonly seen in glioma poor prognosis patients.With the continuous development of science and technology, the diagnosis of glioma will tend to the gene and molecular level. Finding specific markers is helpful for the early diagnosis and accurate prognosis of glioma, which provides the possibility for individualized treatment.

In recent years, cellular metallic materials have attracted significant interest for biomedical applications. However, mutually opposing requirements of porous architecture and mechanical strength in conjunction with the high energy absorption capability have restricted their use. Here, we illustrate that electron beam melting can fabricate functionally graded Ti-6Al-4V alloy interconnected mesh structures with a combination of low density (0.5–2 g/cm3), high fatigue strength (∼70 MPa) and energy absorption (∼50 MJ/mg), which is superior to the ordinary uniform cellular structures. The underlying fundamental mechanisms governing the compressive and fatigue behavior of the graded cellular structures are elucidated via in situ tomography experiments and digital volume correlation analyses. It is underscored that during cyclic deformation, the stress can be continuously redistributed because of inhomogeneous mechanical properties and crack formation in constituent meshes, thereby resulting in variation of cyclic ratcheting rate for the graded cellular structures.

β-type titanium porous structure is a new class of solution for implant because it offers excellent combinations of high strength and low Young's modulus. This work investigated the influence of porosity variation in electron beam melting (EBM)-produced β-type Ti2448 alloy samples on the mechanical properties including super-elastic property, Young's modulus, compressive strength and fatigue properties. The relationship between the misorientation angle of adjacent grains and fatigue crack deflection behaviors was also observed. The super-elastic property is improved as the porosity of samples increases because of increasing tensile/compressive ratio. For the first time, the position of fatigue crack initiation is defined in stress-strain curves based on the variation of the fatigue cyclic loops. The unique manufacturing process of EBM results in the generation of different sizes of grains, and the apparent fatigue crack deflection occurs at the grain boundaries in the columnar grain zone due to substantial misorientation between adjacent grains. Compared with Ti-6Al-4V samples, the Ti2448 porous samples exhibit a higher normalized fatigue strength owing to super-elastic property, greater plastic zone ahead of the fatigue crack tip and the crack deflection behavior.

This study investigates the differences in the microstructure, defects and mechanical behavior of porous structures from a β-type Ti 24Nb 4Zr 8Sn manufactured by electron beam melting (EBM) and selective laser melting (SLM). The phases, size and shape of melt pool, volume and distribution of defects are analyzed and correlated to the compressive mechanical and fatigue properties. Due to different powder bed temperatures, the microstructure of EBM and SLM samples consists of α+β phases and a single β phase, respectively. The faster cooling rate during SLM promotes the formation of fine β dendrites, which leads to a higher compressive strength (50 ± 0.9 MPa) and lower Young's Modulus (0.95 ± 0.05 GPa) in comparison to the EBM parts (45 ± 1.1 MPa and 1.34 ± 0.04 GPa respectively). The large defects present within solid strut are likely a result of tin vaporization. The tin vapor is more easily trapped during the SLM process due to a smaller laser spot size and a faster cooling rate. This results in a 10 times increase in the number of defects. These defects have a limited influence on both the static properties and low stresses level fatigue strength, but it causes a reduced and variable fatigue life at high stresses level.

This chapter discusses the design, fabrication, mechanical properties, and biocompatibilities of Ti-6Al-4V cellular structures fabricated by the electron beam melting (EBM) technique. Stochastic foams and reticulated meshes with different porosities were used to reveal the underlying mechanisms, which determine the Young modulus, deformation behavior, and fatigue failure process. in vivo investigations indicated that EBM cellular structures not only exhibited desired mechanical properties but also good biocompatibility. The future development trends of Ti-6Al-4V cellular structures for biomedical applications were also discussed.

Ti-6Al-4V reticulated meshes with different elements (cubic, G7 and rhombic dodecahedron) in Materialise software were fabricated by additive manufacturing using the electron beam melting (EBM) method, and the effects of cell shape on the mechanical properties of these samples were studied. The results showed that these cellular structures with porosities of 88-58% had compressive strength and elastic modulus in the range 10-300MPa and 0.5-15GPa, respectively. The compressive strength and deformation behavior of these meshes were determined by the coupling of the buckling and bending deformation of struts. Meshes that were dominated by buckling deformation showed relatively high collapse strength and were prone to exhibit brittle characteristics in their stress-strain curves. For meshes dominated by bending deformation, the elastic deformation corresponded well to the Gibson-Ashby model. By enhancing the effect of bending deformation, the stress-strain curve characteristics can change from brittle to ductile (the smooth plateau area). Therefore, Ti-6Al-4V cellular solids with high strength, low modulus and desirable deformation behavior could be fabricated through the cell shape design using the EBM technique.

The argument from faultless disagreement employed by the relativist purports to show that contextualism falls short of explaining cases of faultless disagreement. The demonstration is intended to give credence to the relativist semantics of epistemic modality expressions. In this paper we present some cases showing that even though cases of faultless disagreement do reveal some intrinsic features of epistemic modality claims, they do not support the relativist semantics. The sophistication of faultless disagreement goes beyond what the relativist semantics can cope with. We also advance an epistemologically oriented proposal to account for faultless disagreement.

Shock-wave/boundary-layer interaction (SWBLI) in a transonic turbine cascade was researched numerically using large eddy simulation (LES) and the results were compared with experimental data to verify the method. The investigation indicated that, the LES reproduced the SWBLI process accurately. The flow details in the SWBLI region appeared highly three-dimensional characteristic. The contours of span-wise vorticity on suction surface in the separation bubble were presented to indicate the transient flow development. The surface limiting streamlines turned out to be two counter-rotating vortices. The SWBLI caused a pressure fluctuation on the suction side downstream of this region. The maximum value was about 2 per cent of the local mean pressure.

SummaryUltrasonic agitation during electroless plating nickel affects the structure and properties of the deposits. In this work, a complete study was made of the action of ultrasound on the plating rate, micro-hardness, phosphorus content and corrosion properties of electroless plated deposits. It was found that in the presence of the ultrasound, the plating rate and micro-hardness of as-deposited were increased by about 30 and 10 percent respectively, whilst the phosphorus content was decreased from 10.49 to 8.39 at%. The changes in these parameters, in turn, affect the corrosion behaviour of the electroless deposits. The deposit formed with ultrasound exhibited active corrosion characteristics, whilst the deposit formed without ultrasound had a passive behaviour in 0.2 M H2SO4 solution.