Stress-Strain Partitioning Analysis in Dual Phase Steels

Dual-Phase (DP) steels are made of ductile ferrite phase and hard martensite phase.Although it became crucial in progress of automotive industry to save fuel consumption and reduce total weight of vehicles,we need more accurate estimation of distribution to mechanical properties in total amounts of specimen.DP steels have considerable difference of mechanical levels in each phase including ferrite and martensite.That is why this study focuses on deconvolution of experimental tensile curve into ferrite and martensite using EBSD for calculation of phase volume fractions and Swift equation.Nanoindentation for certain parameter of each phase was conducted to produce the deconvolution curves.     

An efficient face detection based on color-filtering and its application to smart devices

This paper proposes a means of using facial color to enhance conventional face detectors. To detect face rapidly, the proposed approach adopts a color filtering based efficient region scanning method. The scanning method skips over regions that do not contain candidate faces, based on a facial color membership function. Then it adopts a face/non-face classifier using facial color at the preprocessor of the face detector. This classifier has low computational cost and can reject non-face regions at an early stage of face detection. By integrating the proposed face detector with a kernel based object tracker, a real-time face detection and tracking application is implemented for smart devices. The proposed method considerably reduces the overall computation time and reduces the number of false alarms.     

Preparation of nano-sized Sn powders by phase transformation and their oxidation behavior

Synthesis behavior and microstructural characteristics of nano-sized SnO2 powders were investigated. SnO2 powders were synthesized by controlled heat treatment of nano-sized Sn powders in air. Microstructural observation revealed that the nano-sized SnO2 powders could be successfully prepared by controlled oxidation treatment with a low heating rate and further ball milling. The synthesis behavior was analyzed based on the observed microstructural characteristics dependent on heating rate and milling condition.     

An integrated microchannel with continuous electrodynamic anti-adhesion capability for particle loss reduction in air-based microfluidic chips

In air-based microfluidic chips, particle adhesion to the walls of a microchannel deteriorates its performance and reliability due to structural changes such as channel clogging. In this study, an integrated anti-adhesion microchannel with a continuous electrodynamic anti-adhesion technique, used to detach particles adhered to the wall of a microchannel, was developed for applications using air-based microfluidic chips. Theoretical analysis of particle adhesion and electrodynamic anti-adhesion in a microfluidic channel was addressed based on computational fluid dynamics and electric simulation results. Particle loss due to adhesion to the wall of a microchannel was evaluated by the supply of airborne particles to the I-shaped microchannel and the serpentine microchannel. The reduction of particle loss using the electrodynamic anti-adhesion technique was then analyzed. In the I-shaped microchannel for the evaluation of penetration efficiency, most of the upstream particles penetrated the channel, making particle loss rare. The measured average penetration efficiency was 93.2%. On the other hand, heavy particle loss occurred in the curved section of the serpentine microchannel. The proposed technique was adopted to decrease particle loss. For the 1.28?μm polystyrene latex, the initial particle loss (0?V) was 94?±?0.6%, while the particle loss with the proposed technique (3?kV at 1?kHz) was 78?±?1.3%. The maximum reduction in particle loss was 17.9%. According to the experimental results, the proposed technique could enhance the sampling performance of air-based microfluidic chips.     

Improvement of ultra-soft soil using prefabricated vertical drains

A case study of using prefabricated vertical drains (PVDs) to accelerate the consolidation of an ultra-soft fine-grained soil with high moisture content for a land reclamation project is described in this paper. Large-scale laboratory model tests were carried out to assess the suitability of the selected PVD and the effectiveness of the PVD in the consolidation of the ultra-soft soil. The model tests indicate that the discharge capacity of the drain can decrease substantially after the drain has experienced large deformations. To overcome this problem, PVDs were installed in two rounds. The first round was before the application of surcharge, and the second round was after substantial settlements have taken place. Field instrumentations were utilized to monitor the performance of PVDs during consolidation. The monitored settlement and pore water pressure results are presented and discussed. The study shows that it is effective to use PVD for the consolidation of the ultra-soft soil if special care has been taken in selection and installation of PVD and in fill placement to overcome the difficulties involved in the consolidation of ultra-soft soil.     

Synthesis of well-aligned carbon nanotubes with open tips

Large amounts of well-aligned carbon nanotubes (CNTs) with open tips have been produced by pyrolysis of iron(II) phthalocyanine. The aligned CNTs have an average length about 10 μm and diameters ranging from 92 to 229 nm. Some of produced CNTs showed Y-junction structure due to the self-joint growth of two neighboring CNTs. The well-aligned CNTs indicated a bamboo-shaped multiwalled structure and fairly good crystallinity. The aligned CNTs follow tip growth mechanism.     

The gain decompression effect and its applications to very fast wavelength conversions

The gain recovery in a semiconductor optical amplifier (SOA) follows a two-step process: (1) an ultrafast gain recovery process through the nonlinear gain decompression effect and (2) a slower carrier recovery process that is dominated by carrier effects like Auger recombination or carrier diffusion. We discuss and numerically demonstrate how to control this decompression gain and apply it to very fast wavelength conversions.     

Synthesis of Size-Controlled SrFe12O19 Using Modified Spray Pyrolysis–Calcination Method and Their Magnetic Properties

Strontium hexaferrite (SrFe₁₂O₁₉, SrM) suitable for high-performance permanent magnet applications was synthesized by salt-assisted ultrasonic spray pyrolysis (SA-USP) and subsequent calcination. To control the particle size, the intermediate phase of SrM was collected by SA-USP and various sizes of SrM were obtained by calcining the as-prepared sample at temperatures ranging from 800°C to 1050°C. The synthesized SrM was magnetically aligned by using an external magnetic field to improve remanence. The synthesized particles were of nano- to submicron scale and nonagglomerated. The magnetic properties and squareness of the material depended on the particle size and distribution. Additionally, the NaCl added during synthesis facilitated the formation of nonagglomerated particles, while enhancing and controlling particle growth. The optimum magnetic properties were achieved at calcination temperature of 1000°C, resulting in coercivity of 5646 Oe, saturation magnetization of 73.3 emu/g, and remanence of 59.1 emu/g (80.6% of M _s).     

Novel one-step route to induce long-term lotus leaf-like hydrophobicity in polyester fabric

Lotus leaf-like hydrophobic pattern development through a facile and commercially applicable method has always been an issue for the textile industry. In this study, a novel commercially applicable method for the development of such patterns without affecting the structural integrity of the polyester textile was proposed. Photoresist molds with pattern dimensions similar to the lotus leaf surface were fabricated by a conventional photolithography process. The inverse of these patterns was obtained by a Ni electroforming process conducted on the fabricated photoresist molds to form Ni molds, which were utilized to transfer the lotus-leaf like patterns onto polyester fabric by one-step hot embossing method. The surface morphology of the polyester fabric before and after pattern transfer was studied by an optical microscope and field emission scanning electron microscopy images, respectively. The results revealed a successful transfer of patterns. Three-dimensional profiler data analysis provided the information regarding roughness of the embossed surfaces. A high surface roughness (R_a = 48 μm) was achieved after the development of lotus leaf-like patterns on the polymer textile. Contact angle hysteresis was studied using the contact angle analyzer.