On the Machinability and Surface Finish of Superalloy GH909 Under Dry Cutting Conditions

<div><p>GH 909 alloy is a kind of low thermal expansion superalloy with high strength and low expansion coefficient. It is mainly used for manufacturing of aero-engine turbine casings, sealing ring, vanes and other gap control parts, to improve the working efficiency and thrust of the engine as well as to reduce gas loss and fuel consumption. However, the machinability is still a problem that restricts the application of GH909. This paper investigated the machinability referring to cutting forces, surface quality and tool wear in the milling process with carbide tool. The main conclusions are: (1) GH909 has similar machinability with other Nickel-based alloys, cutting velocity does not have great influence on cutting forces for small radial cutting depth. (2) Good machined surface quality can be get for cutting velocity around 70m/min. (3) To get good tool performance and reduce tool wear rate, cutting velocity can be set to no larger than 80m/min.</p></div

Supplementary document for Optimized principal component analysis for camera spectral sensitivity estimation - 6473374.pdf

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Display gamut comparison

Supplementary file to the Manuscript 47280

Video_1_A Soft Robotic Wearable Wrist Device for Kinesthetic Haptic Feedback.MP4

<p>Advances in soft robotics provide a unique approach for delivering haptic feedback to a user by a soft wearable device. Such devices can apply forces directly on the human joints, while still maintaining the safety and flexibility necessary for use in close proximity to the human body. To take advantage of these properties, we present a new haptic wrist device using pressure-driven soft actuators called reverse pneumatic artificial muscles (rPAMs) mounted on four sides of the wrist. These actuators are originally pre-strained and release compressive stress under pressure, applying a safe torque around the wrist joints while being compact and portable, representing the first soft haptic device capable of real-time feedback. To demonstrate the functional utility of this device, we created a virtual path-following task, wherein the user employs the motion of their wrist to control their embodied agent. We used the haptic wrist device to assist the user in following the path and study their performance with and without haptic feedback in multiple scenarios. Our results quantify the effect of wearable soft robotic haptic feedback on user performance. Specifically, we observed that our haptic feedback system improved the performance of users following complicated paths in a statistically significant manner, but did not show improvement for simple linear paths. Based on our findings, we anticipate broader applications of wearable soft robotic haptic devices toward intuitive user interactions with robots, computers, and other users.</p

Writing Highly Ordered Macroscopic Patterns in Cylindrical Block Polymer Thin Films via Raster Solvent Vapor Annealing and Soft Shear

Block polymers (BPs) potentially can be used to template large arrays of nanopatterns for advanced nanotechnologies. However, the practical utilization of directed BP self-assembly typically requires guide patterns of relatively small size scales. In this work, the macroscopic alignment of block polymer cylinders on a template-free substrate is achieved through raster solvent vapor annealing combined with soft shear (RSVA-SS). Spatial control over nanoscale structures is realized by using a solvent vapor delivery nozzle, poly­(dimethylsiloxane) shearing pad, and motorized stage. Complex patterns including dashes, crossed lines, and curves are demonstrated, along with the ability for large area alignment and scale-up for industry applications. The unique ability to directly write macroscopic patterns with microscopically aligned BP nanostructures will open new avenues of applied research in nanotechnology

Residual Stresses Analysis in Ball end Milling of Nickel-Based Superalloy Inconel 718

<div><p>Inconel 718 is widely used in the aviation, space, automotive and biomedical industries because of its outstanding properties. Near-surface residual stresses that are induced by ball end milling in Inconel 718 can be crucial for the performance and service time of the machined parts. In this paper, the influences of cutting conditions, including the use of cutting parameters, cutting fluid and spindle angles, on the residual stresses in the ball end milling process of Inconel 718 alloy were investigated experimentally. X-ray diffraction measurements reveal that residual stress distributions are highly influenced by cutting parameters, especially the depth of cut and cutting speed. The milling operation with cooling induces more compressive stresses trend and the magnitude of the residual stresses increases in the tensile direction with the increase of spindle angles. These cutting induced effects were further discussed with respect to thermal- mechanical coupling theory and some observations made by optical microscopy. From this investigation, it is suggested that the machining process parameters are not the smaller the better for the control of residual stresses in the ball end milling process of Inconel 718.</p></div

Optimal warranty option and post-warranty maintenance strategy under a warranty menu: from a consumer perspective

As manufacturers continue to provide new and unique products and services for their customers, we argue that warranty menus with differentiated options are an often-overlooked unique selling point. Meanwhile, there is a huge swathe of customers who own durable products which are still in use even after the expiration of a warranty. It is in this area that we develop a research perspective which urges customers to consider warranty plans and post-warranty maintenance strategies simultaneously when making a purchasing decision. In this paper, through the lens of a consumer, we propose an integrated model of warranty and post-warranty maintenance under a flexible renewable warranty. This model takes into account repair limits and multiple failure types with time-varying probabilities. As part of this, a new post-warranty maintenance strategy is designed, in which the repair time-based corrective replacement and the age-based preventive replacement are combined. The life cycle cost rate of the product is minimised by a synthetic decision-making about the consumer’s warranty purchase and post-warranty maintenance strategy. Numerical studies show that there exists a joint optimal solution, which can help the customer to develop an optimal overall warranty-maintenance strategy under the warranty menu with minimised cost rate.</p

An Investigation of the Pathways for Oxygen/Sulfur Scramblings during the Copolymerization of Carbon Disulfide and Oxetane

The catalytic coupling of oxetane, the symmetric isomer of propylene oxide, with carbon disulfide has been investigated utilizing (salen)­CrCl in the presence of various onium salts. Oxygen and sulfur atom exchange was observed in both the polymeric and cyclic carbonate products. The coupling of oxetane and CS₂ was selective for copolymer formation over a wide range of reaction conditions. Five different polymer linkages and two cyclic products were determined by ¹H and ¹³C NMR spectroscopy, and these results were consistent with <i>in situ</i> infrared spectroscopic monitoring of the process. The major cyclic product produced in the coupling process was trimethylene trithiocarbonate, which was isolated and characterized by single crystal X-ray crystallography. Upon increasing the CS₂/oxetane feed ratio, a decrease in the O/S scrambling occurred. The reaction temperature had the most significant effect on the O/S exchange process, increasing exchange with increasing temperature. The presence of the onium salt initiator both accelerated the coupling process and promoted O/S scrambling. COS (observed), and CO₂ intermediates are proposed in the reactions leading to various polymeric linkages

An Investigation of the Pathways for Oxygen/Sulfur Scramblings during the Copolymerization of Carbon Disulfide and Oxetane

The catalytic coupling of oxetane, the symmetric isomer of propylene oxide, with carbon disulfide has been investigated utilizing (salen)­CrCl in the presence of various onium salts. Oxygen and sulfur atom exchange was observed in both the polymeric and cyclic carbonate products. The coupling of oxetane and CS₂ was selective for copolymer formation over a wide range of reaction conditions. Five different polymer linkages and two cyclic products were determined by ¹H and ¹³C NMR spectroscopy, and these results were consistent with <i>in situ</i> infrared spectroscopic monitoring of the process. The major cyclic product produced in the coupling process was trimethylene trithiocarbonate, which was isolated and characterized by single crystal X-ray crystallography. Upon increasing the CS₂/oxetane feed ratio, a decrease in the O/S scrambling occurred. The reaction temperature had the most significant effect on the O/S exchange process, increasing exchange with increasing temperature. The presence of the onium salt initiator both accelerated the coupling process and promoted O/S scrambling. COS (observed), and CO₂ intermediates are proposed in the reactions leading to various polymeric linkages

Domain selection combined with improved cloning strategy for high throughput expression of higher eukaryotic proteins-2

<p><b>Copyright information:</b></p><p>Taken from "Domain selection combined with improved cloning strategy for high throughput expression of higher eukaryotic proteins"</p><p>http://www.biomedcentral.com/1472-6750/7/45</p><p>BMC Biotechnology 2007;7():45-45.</p><p>Published online 30 Jul 2007</p><p>PMCID:PMC1950093.</p><p></p