Preparation ofZincOxide Nanoparticles by UV-IrradiationMethod in Two Different Media

The zinc oxidenanoparticles(ZnO NPs) were prepared in two media. The first one was in an aqueous medium resulting from the reaction of urea with zinc acetate at 0.3M concentration in both of them in deionized water. The second medium is a polymeric solution which is a dissolving of 4% polyvinyl alcohol (PVA)in deionized water with zinc acetate. The nanoparticles were obtained after the two media were irradiated with ultraviolet rays for 30 min. According to the characterization of the XRD, FESEM, and UV-visible, the polymeric medium gives a less granular size in addition to its ease of use and handling.

Finishing of Tubes using Bonded Magnetic Abrasive Powder in an Abrasive Medium

Magnetic abrasive flow finishing (MAFF) is an unconventional process capable of producing fine finishing with machining forces controlled by a magnetic field. This process can be utilized for hard to achieve inner surfaces through the activity of extrusion pressure, combined with abrasion activity of a magnetic abrasive powder (MAP) in a polymeric medium. MAP is the key component in securing systematic removal of material and a decent surface finish in MAFF. The research background disclosed various methods such as sintering, adhesive based, mechanical alloying, plasma based, chemical, etc. for the production of bonded MAP. This investigation proposes bonded MAP produced by mechanical alloying followed by heat treatment. The experiments have been conducted on aluminum tubes to investigate the influence of different parameters like magnetic field density, extrusion pressure and number of working cycles. The bonded magnetic abrasive powder used in MAFF is very effective to finish tubes’ inner surfaces and finishing is significantly improved after processing.

Piezoresistive Response of Integrated CNT Yarns under Compression and Tension: The Effect of Lateral Constraint

Carbon nanotube (CNT) yarns are fiber-like materials that exhibit excellent mechanical, electrical and thermal properties. More importantly, they exhibit a piezoresistive response that can be tapped for sensing purposes. The objective of this study is to determine experimentally the piezoresistive response of CNT yarns that are embedded in a polymeric medium while subjected to either compression or tension, and compare it with that of the free or unconstrained CNT yarns. The rationale for this study is the need to know the response of the CNT yarn while in a medium, which provides a lateral constraint to the CNT yarn thus mimicking the response of integrated CNT yarn sensors. The experimental program will include the fabrication of samples and their electromechanical characterization. The CNT yarns are integrated in polymeric beams and subjected to four-point bending, allowing the determination of their response under tension and compression. The electrical resistance data from an Inductance-Capacitance-Resistance (LCR) device is used with the data acquired from the mechanical testing system to determine the piezoresistive response of the CNT yarns. This data and information will be used for future modeling efforts and to study the phenomena that occur when CNT yarns are integrated in polymeric and composite materials and structures.