Surface Erosion of Carbon Steel 1045 During Waterjet Peening

The present study investigates the effect of waterjet treatment on the surface characteristics of the carbon steel 1045. The effect of waterjet treatment parameters namely number of jet passes and pressure was investigated. An increase in the number of jet passes as well as pressure leads to a higher roughness and more erosion of the surface. The damage features consist of various fracture mechanism modes occurred at the initial and evolved damage stage. The ferrite phase experienced more damage than the pearlite phase. However, the damage was more concentrated along the grain boundaries. The shearing force from the jet lateral flow raised the circumferential rim and created lateral cracks and sub-tunnels which might eventually be removed in the subsequent jet passes. The hardness of the treated specimens increased with an increase in the number of jet passes and pressure

Biomechanical properties of masticatory balance in cases with RPDs—The influence of preferred and nonpreferred chewing side: A pilot study

Objectives Removable partial dentures (RPDs) are inserted with the aim to restore masticatory function. There is however inconsistent evidence supporting the alleged improvements, posterior occlusal contacts being one of the decisive factors. We hypothesized that the distribution of abutment teeth in RPDs influences masticatory performance and functional parameters. To evaluate the masticatory performance and functional parameters in patients with a RPD using a single mathematical parameter (tilting index [TI]) for both jaws that predicts biomechanical behavior on the basis of the distribution of abutment teeth. Materials and Methods Masticatory performance was measured in patients wearing long-time adapted RPDs using the standardized test food optocal, yielding the mean particle size (X$_{50}$). Mastication on the preferred and nonpreferred chewing sides was analyzed. Total muscle work (TMW) was calculated using bipolar electromyographic recordings of the masseter and anterior temporalis muscle. Functional parameters were subjected to multiple linear regression analysis including X$_{50}$ as a dependent variable and functional units (FU), the number of teeth, bite forces, and sagittal and frontal components of TI (TI α and TI β) as independent variables. Results When the preferred chewing side was tested, none of the investigated parameters correlated significantly with X$_{50}$. In contrast, chewing on the nonpreferred side was correlated significantly with performance for most variables (p < .05). This means that increased dental support improved chewing performance with RPDs under these conditions. Conclusions In well-adapted RPDs, the distribution of abutment teeth as expressed by the tilting index seems to be of subordinate importance for masticatory performance

Large-Scale Data Management for Earth Observation Data - Challenges and Opportunities

Earth observation (EO) has witnessed a growing interest in research and industry, as it covers a wide range of different applications, ranging from land monitoring, climate change detection, and emergency management to atmosphere monitoring, among others. Due to the sheer size and heterogeneity of the data, EO poses tremendous challenges to the payload ground segment, to receive, store, process, and preserve the data for later investigation by end users. In this paper we describe the challenges of large-scale data management based on observations from a real system employed for EO at the German Remote Sensing Data Center. We outline research opportunities, which can serve as starting points to spark new research efforts in the management of large volumes of scientific data

Influence of Waterjet Peening and Smoothing on the Material Surface and Properties of Stainless Steel 304

The present study investigates a combined effect of waterjet peening and smoothing on the surface of austenitic stainless steel 304. An analysis of surface finish and the change in hardness were evaluated. The waterjet treatment on the surface was conducted in steps with multiple passes. Initially, the surface was treated with a higher energy and later with a lower energy of the water droplets. The surfaces treated with multiple steps of decreasing energy produced a smoother surface with lower peak heights and a slightly higher increase in the hardness than the surface treated with only a single step. The hardening layer was also maintained during the later step treatment. The combined action of surface hardening and smoothing using multiple steps in waterjet treatment is useful in increasing the hardness and reducing the roughness of the surface

Effect of Multiple Passes Treatment in Waterjet Peening on Fatigue Performance

The influence of waterjet peening on the residual stresses and fatigue performance of AISI 304 is investigated. The specimen surfaces were treated with multiple jet passes. The fatigue strength was evaluated using an alternating bending fatigue tester. The results of XRD measurements showed that a higher amount of compressive residual stresses is induced in the treated specimens. This strengthening layer is limited within the first 100 �m below the surface, which had been confirmed by micro hardness measurements. Even though the treated specimens showed compressive residual stresses the fatigue limit is lower than that of the untreated specimens. The roughness of the surface and the resulting notch effect seems to be stronger than the positive effect of the hardened layer

The acetylcholine receptor: double-channel, noncovalent interactions and a possible role for the [delta]-[delta]-disulfide bridge

Spillecke F, Schindler H, Neumann E. The acetylcholine receptor: double-channel, noncovalent interactions and a possible role for the [delta]-[delta]-disulfide bridge. Hoppe-Seyler's Zeitschrift für physiologische Chemie. 1983;364:1220

Sedimentary Signatures of the North Gondwana Margin in Devonian Conodonts from the Geyikdağ Unit in the Eastern Taurides (Southern Turkey): Biostratigraphical Implications

Devonian Conodonts from the Geyikdağ Unit in the Eastern Taurides (Southern Turkey): Biostratigraphical Implication