The effect of iron additions on the microstructure and properties of the “Tribaloy” Co-Mo-Cr-Si wear resistant alloys

The effect of iron additions in the range 5 to 15 wt % iron inclusive on the microstructure and properties of two Co-Mn-Cr-Si wear resistant alloys (Tribaloys T400 and T800) has been investigated. Iron additions were found to stabilize the f c c form of the cobalt solid solution, to give a fully eutectic matrix and to decrease the volume fraction of the primary Laves phase. These microstructural modifications have little effect on the plane strain fracture toughness but result in a significant increase in the modulus of rupture. The addition of iron induces only minor changes in the corrosion and oxidation resistance of T800, whereas the performance of T400 deteriorates.     

A Glass–Ceramic Derived from High TiO2-Containing Slag: Microstructural Development and Mechanical Behavior

A novel glass–ceramic material was developed from the melt of a TiO₂-containing iron-making slag with additional waste glass. The high percentage (∼20 wt% TiO₂) of this network-modifying oxide has promoted a crystallization of the parent glass, resulting in a fine-grained, homogeneous polycrystalline material with high mechanical properties ( E =120 GPa, flexural strength=∼180 MPa, and Vickers hardness=7 GPa) after a heat treatment at 1100°C for 2 h. The room temperature and elevated temperature fracture toughness were also studied. The main crystalline phases of the glass–ceramic material were of the pyroxene series until heat-treatment temperature reached 1000°C, at which titanium-rich perovskite and armalcolite crystals became the dominant phases. The end material is high-strength, aesthetically acceptable (metallic gray or opaque brown colored), and suitable for structural and architectural applications.     

Functionally graded nickel-aluminide and iron-aluminide coatings produced via laser cladding

Functionally graded nickel-aluminide and iron-aluminide in the form of superimposed clad layers up to 4 mm total thickness were produced on nickel and on iron based substrates, respectively. A continuous wave carbon dioxide laser and two separate powder feeders were employed. The processing parameters were: 1.8 kW laser power, 3 mm beam diameter, and 7 mm s^–1 traverse speed. A series of single clad layers with various Al contents were first produced in order to obtain fundamental data required for the processing of functionally graded materials. Functionally graded Ni-Al and Fe-Al coatings (up to three layers) were produced by successive deposition of clad layers normal to the substrate surface.Compositional control was achieved by keeping the powder flow of Ni or Fe constant and changing the flow rate of Al. Microstructures are interpreted and discussed in relation to aluminides based on the Ni-Al and Fe-Al systems.     

Effect of irradiation on the mechanical properties of commercially produced Nb3Sn tapes

The effect of neutron irradiation on the mechanical properties of commercially produced Nb₃Sn tapes has been investigated using scanning electron microscopy, sound velocity measurements, tensile and three-point bend tests. The elastic moduli show an increase on irradiation which is independent of dose in the range 4×10²¹ to 4×10²³ neutrons m^–2. The majority of the Nb₃Sn tapes show no evidence of significant amounts of plastic deformation prior to failure, which occurs by the intergranular fracture of the Nb₃Sn layers followed immediately by ductile overload failures of the niobium core. The latter changes to a more brittle failure on irradiation and in tapes containing ZrO₂ particles. The fracture stress decreases for doses up to 10²³ neutrons m^–2 but increases at higher doses. Irradiation reduces the critical stress intensity factorK _c, butK _c and the fracture stress are increased in tapes containing ZrO₂. These results are discussed in terms of various micro-structural features and previously determined radiation damage.     

The effect of an amphiphilic self‐assembled lipid lamellar phase on the relief of dry skin

Humectant and occlusive technologies have traditionally been used for the treatment of dry skin. Originally, non‐lamellar‐forming ingredients were used such as petrolatum but recent research has shown the advantage of using lamellar‐forming ingredients such as ceramides, pseudoceramides and phospholipids in the relief of dry skin. Nevertheless, the importance of using lipid‐phase transition inducers, such as long‐chain fatty acids, has not been studied clinically. The evaluation of a novel complex of lipophilic ingredients was of interest: cetyl alcohol, isostearyl isostearate, potassium cetyl phosphate, cetyl behenate and behenic acid. The combination of all these ingredients was shown to be more effective than any single component in water vapour transmission rate studies. This was thought to be owing to the formation of a unique structural organization of the lipids upon dry‐down from an O/W emulsion as was examined by X‐ray diffraction and optical microscopy. When evaluated clinically in a randomized double‐blind and vehicle‐controlled moisturization efficacy trial, this novel blend of ingredients was shown to not only improve the visible signs of skin dryness to a significantly greater extent than a comparable mineral oil‐containing vehicle but also then maintain a better skin condition during the regression no‐treatment phase of the study. This combination of ingredients offers a new technology option for the treatment of dry skin.     

Advances in estimation methods of vegetation water content based on optical remote sensing techniques

Quantitative estimation of vegetation water content(VWC) using optical remote sensing techniques is helpful in forest fire as-sessment,agricultural drought monitoring and crop yield estimation.This paper reviews the research advances of VWC retrieval using spectral reflectance,spectral water index and radiative transfer model(RTM) methods.It also evaluates the reli-ability of VWC estimation using spectral water index from the observation data and the RTM.Focusing on two main definitions of VWC—the fuel mois...     

Dry skin, moisturization and corneodesmolysis

The process leading to the loss of corneocytes form the skin surface is termed desquamation. In healthy skin it is an orderly and essentially invisible process whereby individual or small groups of corneocytes detach from neighbouring cells to be lost to the environment and replaced by younger cells from the deeper layers. Desquamation is carefully controlled to ensure that corneum cohesion and integrity, and hence tissue thickness, is maintained. The most important components of the corneocytes contributing towards intercellular cohesion are the corneodesmosomes and lipids. Corneodesmosomes are proteinaceous complexes which effectively rivet corneocytes together. The intercellular lipids, primarily responsible for the water barrier, also provide part of the extracellular cement. In addition, the shape of the corneocyte itself plays a role in stratum corneum cohesion. Through interdigitation along their peripheral edges, adjacent corneocytes become physically locked together, a process which reinforces the integrity of the tissue. For effective desquamation to occur corneodesmosomes must be degraded: a process catalysed by serine proteases present within the intercellular space and facilitated by subtle changes in lipid composition and phase behaviour. Ultimately, it is the availability of free water which controls corneodesmolysis. In healthy skin this proteolytic process leaves relatively few corneodesmosomes intact in the most superficial layers. By contrast, in chronic and acute dry skin conditions, corneodesmosomal degradation and hence the final stages of desquamation are perturbed, leading to the characteristic formation of visible, powdery flakes on the skin surface. The inability to degrade these structures ultimately reflects a decreased hydrolytic activity of the desquamatory enzymes, either through reduced synthesis of the enzymes, inherent loss of activity, leaching from the surface layers of the corneum or changes in the surrounding lipid-rich microenvironment, which may indirectly reduce enzyme functionality. Increased understanding of the desquamation process is providing new insights into the mode of action of current moisturizing ingredients and is offering opportunities to develop novel therapies for preventing and correcting dry skin.