Interference lithography has proven to be a useful technique for generating periodic sub-diffraction limited nanostructures. Interference lithography can be implemented by exposing a photoresist polymer to laser light using a two-beam arrangement or a one-beam configuration based on a Lloyd’s Mirror Interferometer. For typical photoresist layers, an anti-reflection coating must be deposited on the substrate to prevent adverse reflections from cancelling the holographic pattern of the interfering beams. For silicon substrates, such coatings are typically multilayered and complex in composition. By thinning the photoresist layer to a thickness well below the quarter wavelength of the exposing beam, we demonstrate that interference gratings can be generated without an anti-reflection coating on the substrate. We used ammonium dichromate doped polyvinyl alcohol as the positive photoresist because it provides excellent pinhole free layers down to thicknesses of 40 nm, and can be cross-linked by a low-cost single mode 457 nm laser and etched in water. Gratings with a period of 320 nm and depth of 4 nm were realized, as well as a variety of morphologies depending on the photoresist thickness. This simplified interference lithography technique promises to be useful for generating periodic nanostructures with high fidelity and minimal substrate treatments.

The growth mechanism and the barrier performance of Al2O3, SiO2 and a binary Si-Al oxide (SiAlxOy) deposited by spatial atomic layer deposition (SALD) were investigated. Alumina and silica were deposited by TMA and BDEAS with growth-per-cycles (GPC) of 0.16 and 0.013 nm, respectively. Interestingly a significant higher GPC of 0.225 nm was found for SiAlxOy. Although alumina in principle has excellent barrier properties, the films easily degraded and lose their barrier performance if exposed to water vapor at elevated temperatures. Therefore, the barrier performances of these films were investigated under harsh environment conditions. We found that the barrier performance of 100 nm Al2O3 failed in less than one day at 70 °C with 70 % relative humidity, whereas 100 nm SiAlxOy sustained for approximately one week. However, the resistivity of those barrier systems was significantly improved by inserting a single 3.3 nm SiO2 layer into the barrier films. In this way the barrier system withstands up to 5 months and the intrinsic water vapor transition rate was reduced by two to three orders of magnitude to ∼10-4 g/m2/day at these tough aging conditions.

Among different efforts to increase the competitiveness of lithium-ion batteries (LIBs) in the energy storage marketplace, reducing the cost of production is a major effort by the LIB industry. This work proposes a synthesis method to decrease the production cost for LiFePO4, by synthesizing the material through an open-air environment solid state reaction.

The lithium (Li)-ion battery is a member of the family of rechargeable batteries. In our approach, iron phosphate (FePO4) powder is preheated to eliminate moisture. Once dried, the FePO4 is mixed with lithium acetate (CH3COOLi), and the mixture is heated in a tube furnace. The solid-state reaction is conducted in an open-air environment. In order to minimize the oxidation of the formed LiFePO4, a modified tube reaction vessel is utilized during synthesis. X-ray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS) are used to characterize the crystal structure and chemical composition of the synthesized material. Furthermore, scanning electron microscopy (SEM) characterization shows the grain size of the formed LiFePO4 to be in the range of 200 nm to 600 nm. Cycling testing of fabricated battery cells using the synthesized LiFePO4 is done using an Arbin Tester.

In this work, we investigate a novel synthesis route for the synthesis of LiFePO4 material that utilizes an ionic liquid/water composite medium. The effect of reaction time and reaction temperature on the crystallinity of synthesized material is investigated through X-ray diffraction (XRD). Morphology is analyzed through scanning electron microscopy (SEM). It is observed that the intensity of peaks corresponding to LiFePO4 increase as reaction time increases, but unwanted peaks are present as well. SEM characterization indicates that various structures are initially formed, but as the reaction time progresses product morphology changes in size.

Typically, composites are lightweight, and high strength and hence are attractive for use in aerospace, automotive applications. For most of the aerospace applications, laminated composites serve as a primary load carrying structure and are subjected to a variety of loadings including transverse impact and fatigue loadings. The typical laminated composites are weak in the transverse direction. Since laminated composites are weak in the transverse direction, when these laminates are subjected to transverse loading, most of the time interlaminar failure occurs in the form of delaminations. Conventional methods of preventing delaminations include improving the design and improving the matrix properties. Although, improving the composite design suppress delaminations to some extent, a substantial amount of compromise with other properties like increase of resin volume fraction, degradation of inplane properties, voids, distortion in fibers and laminate, an increase of cost or process complexities are common. The present day researchers are more focused on improving matrix by nanomaterials such as Carbon Nano Tube(CNT), though the cost is hampering its potential for an industrial prospect. Electrospun nanofibers are being considered as a cheap alternative for vapor grown CNTs and other nanomaterials which involve complex fabrication and application methods in the field of interlaminar reinforcement for polymer matrix composites. Most of the aerospace quality composites are manufactured using prepreg due to the higher percentage of fiber volume fraction and hence higher mechanical properties. Although, nanomaterials have been recognized as a major advancement for improvement of composite material properties, there has been very little effort to fabricate prepregs using nanofibers. The current research focuses on the challenges involved in the fabrication of nanofiber enhanced prepregs and process difficulties and possible solutions for fabricating electrospun nanofiber overlaid prepregs. The effects of heat treatment on electrospun nanofiber overlaid woven fabric on the mechanical properties of both glass and carbon are investigated. A novel technique is proposed for manufacturing of nanofiber engineered prepregs.

In sheet metal forming, rapid cooling of austenitized steel and CRP (cushion-ram pulsation) results in an optimized formability. An analysis is conducted regarding the influence of a stepwise deep drawing process of manganese-boron steel 22MnB5, using an oscillating ram-cushion motion at simultaneous cooling. The stops occurring in stepwise forming provide sufficient time for softening and recovery of forming properties. The microstructure can be adjusted by controlled cooling. In order to examine the newly developed process in more detail, FE simulation is applied. Thus, relevant process and material parameters can be determined. The considered values are required for profound experiments using the forming simulator BAEHR DIL 805 A/D. The softening behavior at defined forming temperatures due to CRP are examined. The experimental results of softening at distinctive temperatures provide a basis for the combined processes of stepwise hot sheet metal forming and simultaneous cooling.

The present paper investigates the use of electric current treatment in improving the drawability of plain carbon steel wire for high strength steel applications. The mechanical properties for wires of composition 0.80C 0.65Mn 0.27Si wt.% of diameters 4.09 and 3.00 mm dry drawn from 10.00 mm rods are characterised. The total number of passes for 4.09 and 3.00 mm diameter wires are 7 and 10 respectively resulting in true strains of 1.79 and 2.41. Samples are treated with electric currents in-between the two drawing stages of 4.09 and 3.00 mm, and tested at both stages in tension, torsion and reverse bending along with control samples for comparison. The applied currents are pulsed at a frequency of 100 Hz with each pulse being approximated by a square wave of loading width 80μs and modest current densities of 7.96 Amm–2. Thus the influence of electric current on the drawability of plain carbon steel wire is assessed between stages of reduction.