In this paper, the extrinsic influence of surface finish and notch on both flexural strength and fracture behavior of the alloy steel Pyrowear 53 when subjected to quasi-static bending is presented and discussed. The influence of surface finish on bevel shaped samples of this alloy steel revealed the isotropic surface finish to carry a higher maximum load during a flexural test. However, from the standpoint of extension, the micro-machined process samples revealed observable improvement in extension (mm) capability when subjected to static bending. Samples of this alloy steel having a funnel notch had a lower maximum load carrying capability when compared one-on-one with the bevel shaped sample. The macroscopic fracture mode and the microscopic features on the fracture surface are presented and discussed in light of shape of the test specimen. The key microscopic mechanisms governing fracture behavior of this novel steel are discussed in light of the role played by intrinsic microstructural features, deformation characteristics of the microstructural constituents and nature of loading.

Metallic mirrors are important components of opto-microfluidic systems for their ability to reflect light. Their use, however, has been limited by the challenges of their integration to microfluidic devices. Here we describe the fabrication of indium (In) micromirrors integrated to microfluidic devices and successfully demonstrate their application to the determination of fluorescence concentration in aqueous solutions by absorbance measurements. The technological route presented here for integrating metallic mirrors to microfluidic devices is fast, simple and inexpensive.

A simpler and cost effective approach, in particular with the use of oleic acid and liquid paraffin has been used to prepare CdTe quantum dots at relatively low temperatures (150-200°C). Compared to the other solvent (capping agents), oleic acid is cheaper, more environment friendly and more stable in air. The as-prepared CdTe quantum dots possess cubic crystallite and exhibit size in the range of 3 nm to 11 nm. This new route reduces the material costs and permits to obtain CdTe quantum dots with a narrow emission (fluorescence) spectra ranging from 602 to 617 nm at room temperatures. In order to investigate the application of the prepared samples as nano LED (nano light emitting device), electroluminescence spectroscopy is studied and it shows the emission to be almost at the similar wavelength as that of fluorescence. This study infers the possible application of CdTe quantum dots as nano LED with an emission in the range of 605-620 nm.

The development of a passive, sonic crystal-based device with unusual properties is reported in this study. This device combines a 1D sonic crystal, a nonlinear medium and an acoustic low-pass filter to allow unidirectional broadband ultrasound propagation as a collimated beam for specialized underwater communication. The signal (220–400 kHz) to be transmitted is first amplitude modulated with a high-frequency ultrasonic carrier wave (2·7–3·25 MHz) and applied to one side of the device. The device then demodulates this signal, and consequently, the original low-frequency signal appears as a collimated beam on the other side. The sonic crystal provides a band-pass acoustic filter through which the high-frequency ultrasonic signal can pass through, and the nonlinear medium then demodulates the signal and also generates the low-frequency sound beam through the parametric array concept. The low-pass filter strips off any remaining high-frequency components and also contributes to the unidirectional property of the device. Design details of the device and experimental data are presented.

This study discussed the synthesis of LiFePO₄/C materials prepared by carbonthermal reduction method and the characterization of obtained composites. X-ray diffraction patterns show the synthesized product is LiFePO₄ phase without any existence of impurity. Scanning electron microscopic images show the synthesized LiFePO₄ particle is nano sized, and carbon forms a conductive network between LiFePO₄ particles. Transmission electron microscopy results indicate carbon successfully coated on the surface of LiFePO₄ particles. Raman spectroscopy shows the coated carbon has low degree of graphitization. Compared with pure LiFePO₄ samples, LiFePO₄/C materials exhibit higher electronic conductivity and better electrochemical properties especially at high rate charge/discharge condition.

Opencast coal mining plays a major role in meeting the demand for fossil fuel. Large capacity haul trucks are being increasingly used to meet this demand. These trucks need well-designed haul roads. Opencast mining also imposes adverse conditions on the area due to substantial overburden lying unreclaimed. The current fly-ash production is about 180 MT that will rise to about 600 MT by 2030 in India. It adversely affects land, air and water resources. Strong effort is required to address this issue. An investigation has been taken up to evaluate the use of both fly ash as well as mine overburden material along with a selected additive to develop an alternative construction material to be used in the sub-base of haul road. This article reports the detailed laboratory investigations carried out on the development of Fly ash Composite Material (FCM) with mine overburden and clinker and determination of their suitability for haul road. Proctor compaction test, Unconfined Compressive Strength (UCS) test, Brazilian Tensile Strength (BTS) test and Scanning Electron Microscopy (SEM) were carried out. The composite with 62% fly ash, 30% overburden and 8% clinker exhibited adequate strength value for the haul road construction.

To investigate the effect of dc-bias field on the domain structures, the authors observed polarization–electric field (P-E) hysteresis loop with corresponding multidomain structures on (001)cub and monodomain structures on (111)cub surfaces. The coercive field was found to increase from 4 kV/cm for the (001) to 9 kV/cm for the (111) orientations. Corresponding changes in the area of the hysteresis loops were observed. Piezoelectric coefficient (d33) was found to increase to (a) 860 pC/N for tetragonal, (b) 1255 pC/N for the rhombohedral and (c) 2100 pC/N for the monoclinic phases on (001)cub surface.

The kinetics of grain boundary triple junctions, grain boundary ridges and grain boundary facets are investigated. A theoretical concept and results of experimental observations and computer simulations of the behavior of these interfacial elements are presented, and their effect on the evolution of grain microstructure in 2D and 3D polycrystals is considered.

In situ characterization techniques are now affording direct interrogation of opaque materials during synthesis and processing. In this work, synchrotron X-ray radiography and tomography were performed at Argonne National Laboratory’s Advanced Photon Source to monitor metallic alloys during melting and solidification. X-ray radiographs of microstructure evolution in Al-7at.%Cu during continuous heating and cooling were obtained; the influence of cooling rate on microstructure evolution was also explored. X-ray tomography results of solidification progression in the mushy zone are also presented. These results demonstrate that synchrotron X-ray radiography and tomography can nondestructively and sequentially reveal metallic alloy melting and solidification over the micron length scale in 2D and 3D. In situ characterization will permit advances in solidification theory and allow for the development of predictive solidification and microstructure evolution models. Feedback from real-time imaging will ultimately enable in-process parameter adjustments to control microstructure evolution.