Durable self-healing super-liquid-repellent fabrics

In this study, fabrics having a superhydrophobic and superoleophobic surface were prepared by a wet-chemistry coating technique using a coating solution containing hydrolyzed fluorinated alkyl silane and fluorinated-alkyl polyhedral oligomeric silsesquioxane. The coating shows remarkable self-healing superhydrophobic and superoleophobic properties and excellent durability against UV light, acid, repeated machine washes, and severe abrasion.

A manifold approach to face recognition from low quality video across illumination and pose using implicit super-resolution

We consider the problem of matching a face in a low resolution query video sequence against a set of higher quality gallery sequences. This problem is of interest in many applications, such as law enforcement. Our main contribution is an extension of the recently proposed Generic Shape-Illumination Manifold (gSIM) framework. Specifically, (i) we show how super-resolution across pose and scale can be achieved implicitly, by off-line learning of subsampling artefacts; (ii) we use this result to propose an extension to the statistical model of the gSIM by compounding it with a hierarchy of subsampling models at multiple scales; and (iii) we describe an extensive empirical evaluation of the method on over 1300 video sequences – we first measure the degradation in performance of the original gSIM algorithm as query sequence resolution is decreased and then show that the proposed extension produces an error reduction in the mean recognition rate of over 50%.

Super-resolution of 3-dimensional scenes

Super-resolution is an image enhancement method that increases the resolution of images and video. Previously this technique could only be applied to 2D scenes. The super-resolution algorithm developed in this thesis creates high-resolution views of 3-dimensional scenes, using low-resolution images captured from varying, unknown positions.

Acceleration of the super bainite transformation through a coarse austenite grain size

The effect of austenite grain size on the kinetics of the isothermal bainitic transformation in a high-carbon super-bainitic steel was investigated. Experimental results showed that the transformation of super bainite was accelerated by a coarse austenite grain size. This is because while coarse austenite grains provide less nucleation sites, it is beneficial for bainite sheaf growth. Meanwhile, there is a critical austenite grain size below which there is a distinct grain size effect and above which it is not evident. © 2014 Elsevier B.V.

Refinement of retained austenite in super-bainitic steel by a deep cryogenic treatment

The effect of a deep cryogenic treatment on the microstructure of a super-bainitic steel was investigated. It was shown that quenching the super-bainitc steel in -196°C liquid nitrogen resulted in the transformation of retained austenite to two phases: ~20 nm thick martensite films and some nano carbides with a ~25 nm diameter. Some refinement of the retained austenite occurred, due to formation of fine martensite laths within the retained austenite. The evolution of these new phases resulted in an increase in the average hardness of the super-bainitic steel from 641 to ~670 HV1. © 2014 ISIJ.

Electrospun fibrous membranes with super-large-strain electric superhydrophobicity

Large-strain elastic superhydrophobicity is highly desirable for its enhanced use performance and functional reliability in mechanically dynamic environments, but remains challenging to develop. Here we have, for the first time, proven that an elastic fibrous membrane after surface hydrophobization can maintain superhydrophobicity during one-directional (uniaxial) stretching to a strain as high as 1500% and two-direction (biaxial) stretching to a strain up to 700%. The fibrous membrane can withstand at least 1,000 cycles of repeated stretching without losing the superhydrophobicity. Stretching slightly increases the membrane air permeability and reduces water breakthrough pressure. It is highly stable in acid and base environments. Such a permeable, highly-elastic superhydrophobic membrane may open up novel applications in membrane separation, healthcare, functional textile and energy fields.

A preliminary study on machinability of super austenitic stainless steel

Stainless steel is the most widely used alloys of steel. The reputed variety of stainless steel having customised material properties as per the design requirements is Duplex Stainless Steel and Austenitic Stainless Steel. The Austenite Stainless Steel alloy has been developed further to be Super Austenitic Stainless Steel (SASS) by increasing the percentage of the alloying elements to form the half or more than the half of the material composition. SASS (Grade-AL-6XN) is an alloy steel containing high percentages of nickel (24%), molybdenum (6%) and chromium (21%). The chemical elements offer high degrees of corrosion resistance, toughness and stability in a large range of hostile environments like petroleum, marine and food processing industries. SASS is often used as a commercially viable substitute to high cost non-ferrous or non-metallic metals. The ability to machine steel effectively and efficiently is of utmost importance in the current competitive market. This paper is an attempt to evaluate the machinability of SASS which has been a classified material so far with very limited research conducted on it. Understanding the machinability of this alloy would assist in the effective forming of this material by metal cutting. The novelty of research associated with this is paper is reasonable taking into consideration the unknowns involved in machining SASS. The experimental design consists of conducting eight milling trials at combination of two different feed rates, 0.1 and 0.15 mm/tooth; cutting speeds, 100 and 150 m/min; Depth of Cut (DoC), 2 and 3 mm and coolant on for all the trials. The cutting tool has two inserts and therefore has two cutting edges. The trial sample is mounted on a dynamometer (type 9257B) to measure the cutting forces during the trials. The cutting force data obtained is later analyzed using DynaWare supplied by Kistler. The machined sample is subjected to surface roughness (Ra) measurement using a 3D optical surface profilometer (Alicona Infinite Focus). A comprehensive metallography process consisting of mounting, polishing and etching was conducted on a before and after machined sample in order to make a comparative analysis of the microstructural changes due to machining. The microstructural images were capture using a digital microscope. The microhardness test were conducted on a Vickers scale (Hv) using a Vickers microhardness tester. Initial bulk hardness testing conducted on the material show that the alloy is having a hardness of 83.4 HRb. This study expects an increase in hardness mostly due to work hardening may be due to phase transformation. The results obtained from the cutting trials are analyzed in order to judge the machinability of the material. Some of the criteria used for machinability evaluation are cutting force analysis, surface texture analysis, metallographic analysis and microhardness analysis. The methodology followed in each aspect of the investigation is similar to and inspired by similar research conducted on other materials. However, the novelty of this research is the investigation of various aspects of machinability and drawing comparisons between each other while attempting to justify each result obtained to the microstructural changes observed which influence the behaviour of the alloy. Due to the limited scope of the paper, machinability criteria such as chip morphology, Metal Removal Rate (MRR) and tool wear are not included in this paper. All aspects are then compared and the optimum machining parameters are justified with a scope for future investigations

Microstructural and surface texture analysis due to machining in Super Austenitic Stainless Steel

Inferior surface quality is a significant problem faced by machinist. The purpose of this study is to present a surface texture analysis undertaken as part of machinability assessment of Super Austenitic Stainless Steel alloy-AL6XN. The surface texture analysis includes measuring the surface roughness and investigating the microstructural behaviour of the machined surfaces. Eight milling trials were conducted using combination of cutting parameters under wet machining. An optical profilometer (non-contact), was used to evaluate the surface texture at three positions. The surface texture was represented using the parameter, average surface roughness. Scanning Electron Microscope was utilised to inspect the machined surface microstructure and co relate with the surface roughness results. Results showed that maximum roughness values recorded at the three positions in the longitudinal direction (perpendicular to the machining grooves) were 1.21 μm (trial 1), 1.63 μm (trial 6) and 1.68 μm (trial 7) respectively whereas the roughness values were greatly reduced in the lateral direction. Also, results showed that the feed rate parameter significantly influences the roughness values compared to the other cutting parameters. The microstructure of the machined surfaces was distorted by the existence of cracks, deformed edges and bands and wear deposition due to machining process.

Impacts of wear and geometry response of the cutting tool on machinability of super austenitic stainless steel

This paper presents a study of tool wear and geometry response whenmachinability tests were applied under milling operations onthe Super Austenitic Stainless Steel alloy AL-6XN. Eight milling trials were executed under two cutting speeds, two feed rates, andtwo depths of cuts. Cutting edge profile measurements were performed to reveal response of cutting edge geometry to the cuttingparameters and wear. A scanning electron microscope (SEM) was used to inspect the cutting edges. Results showed the presenceof various types of wear such as adhesion wear and abrasion wear on the tool rake and flank faces. Adhesion wear represents theformation of the built-up edge, crater wear, and chipping, whereas abrasion wear represents flank wear.Thecommonly formed wearwas crater wear. Therefore, the optimum tool life among the executed cutting trails was identified according to minimum lengthand depth of the crater wear.The profile measurements showed the formation of new geometries for the worn cutting edges due toadhesion and abrasion wear and the cutting parameters.The formation of the built-up edge was observed on the rake face of thecutting tool. The microstructure of the built-up edge was investigated using SEM. The built-up edge was found to have the austeniteshear lamellar structure which is identical to the formed shear lamellae of the produced chip.

CoP2 nanoparticles on reduced graphene oxide sheets as a super-efficient bifunctional electrocatalyst for full water splitting

In this communication, we report an electrocatalyst for full water splitting based on CoP2 nanoparticles grown on reduced graphene oxide sheets (CoP2/RGO). As a novel non-noble-metal electrocatalyst, CoP2/RGO shows an ultra-high catalytic activity in alkaline electrolyte which only requires a cell voltage of 1.56 V to attain a current density of 10 mA cm-2 for full water splitting.

Experimental and finite element analysis of machinability of AL-6XN super austenitic stainless steel

This paper presents a finite element cutting modelbased on physical microstructure to investigate the thermomechanicalbehaviour of AL-6XN Super AusteniticStainless Steel in the primary shear zone. Frozen chip rootsamples were created under dry turning operation to observethe plasticity behaviour occurring in the shear zones to comparewith the model for analysis. Chip samples were generatedunder cutting velocities at 65 and 94 m/min, feed rate at0.2 mm/rev and depth of cut at 1 mm. Temperature on thecutting zone was recorded by infrared thermal camera.Secondary and backscatter electron detectors were used toinvestigate the deformed microstructure and to calculate theplastic strain. Experimental results showed the formation ofmicrocracks (build-up edge triggers) at the chip root stagnationzone of both samples. The austenite phase patterns wereevident against the cutting tool tip in the stagnation zone of thechip root fabricated at 65 m/min. The movement of thesepatterns caused the formation of the slip lines within thegrains. The backscatter diffraction maps showed the formationof special grain boundaries within the slip lines, workhardeninglayer and in the chip region. Strain measurementsin the microstructures of the chip roots fabricated at 94 and65 m/min showed high values of 6.5 and 5.7 (mm/mm) respectively.The finite element model was used to measure thestress, strain, temperature and chip morphology. Numericalresults were compared to the outcomes of the experimentalwork to validate the finite element model. The model validatingprocess showed good agreement between theexperimental and numerical results, and the error values werecalculated. For a 94- and 65-m/min cutting speeds, 7.5 and5.2% were the errors in the strain, 3 and 2.5% were the error inthe temperature and 4.7 and 6.8% were the error in the shearplane angles.