Experimental determination of 3D crack propagation scenario in resistance spot welds of a martensitic stainless steel

International Journal of Fracture - The development of high-performance automotive steels involves increasingly complex chemistries and heat treating sequences, to produce stronger and lighter...     

Correction to: Co-sputtering of Al1−xScxN thin films on Pt(111): a characterization by Raman and IR spectroscopies

Journal of Materials Science -     

Diagenesis of magnetic minerals in the intertidal sediments of the Yangtze Estuary, China, and its environmental significance

In this study, diagenesis of iron oxides in intertidal sediments of the Yangtze Estuary, China, has been investigated by combined environmental magnetic and geochemical methods. The results indicated that the magnetic properties of the sediments were dominated by ferrimagnetic magnetite. The content of Fe, DCB- and AOD-extractable iron oxides correlated positively with the concentration of fine grained magnetite near the superparamagnetic/stable single domain (SP/SSD, approximately 0.03 microm) boundary, and with anti-ferromagnetic minerals (hematite/goethite). The magnetic parameters for core SDK indicated a substantial decrease in magnetite concentration from a depth of approximately 20 cm toward the surface, together with a shift in the grain-size distribution of magnetic minerals toward the coarse end, suggesting selective dissolution of fine grained magnetite under reducing conditions. The reduction of iron oxides inferred from magnetic measurements was supported by the similar decrease in the concentration of Fe and Mn and a lower ratio of Mn/Fe. Magnetic measurements on another core from elsewhere also indicated substantial reductive dissolution of iron oxides. In conjunction with the results of heavy metal analysis, it was suggested that the dissolution of iron oxides had a direct effect on the cycling of heavy metals. Therefore, magnetic measurements may provide useful information as to early diagenesis within intertidal sediments, which greatly influences the behavior of heavy metals in coastal environments.     

Erythropoietin Action in Stress Response,Tissue Maintenance and Metabolism

Erythropoietin (EPO) regulation of red blood cell production and its induction at reduced oxygen tension provides for the important erythropoietic response to ischemic stress. The cloning and production of recombinant human EPO has led to its clinical use in patients with anemia for two and half decades and has facilitated studies of EPO action. Reports of animal and cell models of ischemic stress in vitro and injury suggest potential EPO benefit beyond red blood cell production including vascular endothelial response to increase nitric oxide production, which facilitates oxygen delivery to brain, heart and other non-hematopoietic tissues. This review discusses these and other reports of EPO action beyond red blood cell production, including EPO response affecting metabolism and obesity in animal models. Observations of EPO activity in cell and animal model systems, including mice with tissue specific deletion of EPO receptor (EpoR), suggest the potential for EPO response in metabolism and disease.     

Oxidation of Zircaloy-2 studied using a wedge-shaped specimen

Experiments have been carried out to vary the stress in the oxide layer during oxidation of Zircaloy-2. This was achieved by varying the thickness of the metal substrate, using a specimen with a tapered wedge-shaped cross-section. X-ray diffraction measurements confirmed that the compressive stress level in the oxide was reduced when the metal substrate was thinner. The rate of oxidation was also slower for conditions where the stress was reduced. The results can be interpreted such that transitions in the growth result from sequential cracking of the oxide when sufficient elastic strain energy accumulates and that the cracks then enhance access of oxygen to the metal interface.     

Multiphoton Physics

Abstract

We discuss recent developments in the generation of ultra-intense laser pulses and show how these can be used to study matter in the presence of electric fields that compete with that due to the nucleus. This has led to a very rapid growth in a wide range of multiphoton studies, many of which are represented in this volume.     

Self-Consistent Model for Planar Ferrite Growth in Fe-C-X Alloys

A self-consistent model for non-partitioning planar ferrite growth from alloyed austenite is presented. The model captures the evolution with time of interfacial contact conditions for substitutional and interstitial solutes. Substitutional element solute drag is evaluated in terms of the dissipation of free energy within the interface, and an estimate is provided for the rate of buildup of the alloying element “spike” in austenite. The transport of the alloying elements within the interface region is modeled using a discrete-jump model, while the bulk diffusion of C is treated using a standard continuum treatment. The model is validated against ferrite precipitation and decarburization kinetics in the Fe-Ni-C, Fe-Mn-C, and Fe-Mo-C systems.     

Planar-Based Visual Inertial Navigation: Observability Analysis and Motion Estimation

In this paper, we address the problem of ego-motion estimation by fusing visual and inertial information. The hardware consists of an inertial measurement unit (IMU) and a monocular camera. The camera provides visual observations in the form of features on a horizontal plane. Exploiting the geometric constraint of features on the plane into visual and inertial data, we propose a novel closed form measurement model for this system. Our first contribution in this paper is an observability analysis of the proposed planar-based visual inertial navigation system (VINS). In particular, we prove that the system has only three unobservable states corresponding to global translations parallel to the plane, and rotation around the gravity vector. Hence, compared to general VINS, an advantage of using features on the horizontal plane is that the vertical translation along the normal of the plane becomes observable. As the second contribution, we present a state-space formulation for the pose estimation in the analyzed system and solve it via a modified unscented Kalman filter (UKF). Finally, the findings of the theoretical analysis and 6-DoF motion estimation are validated by simulations as well as using experimental data.     

Effect of clove extract pretreatment and drying conditions on lipid oxidation and sensory discrimination of dried omena (Rastrineobola argentea) fish

Sun‐drying is a low‐cost, low‐technology fish preservation method frequently employed in developing areas. However, the process promotes lipid oxidation and its associated undesired flavours and odours. This study investigated low‐technology solutions for impact on lipid oxidation and sensory attributes of oven‐dried omena fish (Rastrineobola argentea). Two oven‐drying conditions and four doses of clove water extract ‘dip’ pretreatments were studied in a complete factorial design. Lipid oxidation in dried fish was assessed by TBARS, peroxide value and fatty acid analysis by GC‐FID. Results showed that soaking in 10 g L^?1 clove water extract for 1 h and oven‐drying at 150 °C × 30 min significantly reduced TBARS and peroxide values in omena fish by 77% and 79%, respectively, and polyene index showed improved retention of long‐chain polyunsaturated fats, compared to original drying condition. Lastly, panellists of a triangle test were able to discriminate between biscuits made with the modified and original dried fish.