Self-assemblying behaviour of activated microporous carbon microspheres functionalized via water filtration process

Activated carbon spheres are truly innovative materials with their porous micro/nanostructure that gives them tunable and controllable surface properties (i.e. high surface area, size and orientation of pores etc.). They have great potential for applications as adsorbents for cleaning/purification of water, air and chemical substances, catalyst supports, energy storage and conversion, adsorption of chemical warfare agents, filtration and others. Magnetic functionalization of highly porous and high surface areas of activated carbons have received considerable attention for their more sophisticated and advanced utilization as "smart" and "self-assemblying" purposes. In this study, a novel fabrication technique was used to synthesize activated high compressive strength nanoporous carbon spheres. The functionalization via adsorption/impregnation of magnetic substances was occured during a well-known water treatment-filtering route to fill the pores with nano-sized magnetic particles. Unusually active and dynamic interactions of the magnetic phases were observed upon contacting into each other revealing self-assemblying behaviour of activated carbon microspheres. Dynamic magnetical interaction of self assemblying behaviour of these spheres may have further and advanced applications for variety of purposes

Structural Evolution and Microstructural Features of the Hydrodynamically Penetrating Copper Jet of a Shaped Charge

Shaped charges are unique and very effective warhead technology mostly applied to the rocket propelled grenades (RPGs) along with other applications (e.g. perforation of rocky formations in mining, rock drilling and other geological technics etc.). RPG's armour piercing and perforation performances originate from an explosively induced formation of a stretching metallic jet with very high velocities (hypervelocity). The hydrodynamic penetration mechanism of the stretching quasi-solid metallic jet is extremely complex and has not been fully understood. Both the jet with spout-like form and the target (i.e. RHA armour steel) behave hydrodynamically (i.e. incompressible fluid) and yet both solid strangely. The present study, as part of a large-scale customized R&D project, is stopping the penetration of the stretching jet of a RPG rocket within an "add-on" armour system. A series of experimental detonations and explosion of shaped charge munitions was conducted to elucidate the microstructural evolution and microstructural features of the metallic copper jet. Penetrating metallic spout-like jet forms were stopped and apprehended/caught within the inner layers of highly succesful composite based "add-on" armour designs. Structural evolution and microstructural analysis of the penetrating metallic jet were investigated to understand this extraordinary "solid-but behaving like fluid (quasi-solid)" metallic copper jet material. The findings obtained in this study suggest that the effective way of stopping the lethal effects of this weapon could be managed by diverting and/or twisting its linear stretching and penetration pathway.State Planning Organization of Turkish RepublicAuthors would like to thank to the State Planning Organization of Turkish Republic for the support of the Project. Authors would like to thank to the Tetra for their support for the SEM microstructural analysis and EDS studies. Authors would also thank to the researchers and technicians of the Materials Institute of TUBITAK Marmara Research Center for their support and work during the detonation-explosion experiments

Functional honeycomb based composite panels for structural and thermal management applications

Baykara, Tarık (Dogus Author)This study deals with the functional properties of honeycomb panels for structural applications, thermal management and sound/heat insulation to design more eco-friendly products. Using honeycomb panels filled with polyurethane (PU) and Phase Change Materials (PCM) led to fulfill desired properties such as minimum density, high stiffness, rigidity and strength and improved thermal properties and heat insulation. Mechanical responses of such panels were investigated along with thermal measurements. Functional roles in structural and thermal management applications may provide advantages such as low cost and high performance in housing, aerospace, automotive, packaging and transportation sectors

Single-needle electrospinning of PVA hollow nanofibers for core-shell structures

As one of the most promising nanostructures, core-/shell-structured nanofiber has been widely used in many applications such as self-healing, drug and gene delivery, and tissue engineering. Hollow or core-/shell-structured nanofibers have generally been produced using single-needle and/or coaxial electrospinning methods. This method involves occurrence of varying sizes of bead formation. In this study, a single-needle electrospinning technique is applied for investigating the processing parameters affecting the fiber morphology and the bead formation in order to understand this innovative technique for further studies. Results showed that the parameters such as the voltage difference, collector distance and solution concentration have significant effects on the shell fiber morphology and the occurrence of bead formation.Istanbul Development AgencyTurkiye Cumhuriyeti Kalkinma Bakanligi [ISTKA TR10/15/YNK/056, TR10/16/YNY/0016]The authors would like to thank the Istanbul Development Agency for their support through the funding of the Project Nos. ISTKA TR10/15/YNK/056 and TR10/16/YNY/0016

Characterization of the damage mechanism of composites against low velocity ballistic impact using computed tomography (CT) techniques

Baykara, Tarık (Dogus Author)Low velocity impact damages are particularly considered as risky and dangerous since the detection of the damage from the surface is almost impossible for extensive evaluation. The mechanisms of penetration and damage for E-glass reinforced polyester resin composite which was hit by a low velocity projectile has been investigated using computed tomography (CT) scanning techniques. Laminated, 11mm thick plates with [0°/90°] ply architecture with 18 layers were impacted by a 9x19mm FMJ Round Nose 8g bullet with a speed of 380m/s. Since the low velocity impact of the bullet is well below the ballistic limit only a partial penetration has occurred and the kinetic energy is fully absorbed following some local matrix cracking, fiber fractures, delamination and friction-erosion. Computed Tomography (CT) technique is found to be a powerful technique that the full extent of the damage progression in 3-D can be visualized through the interfaces of the composite laminates

Development of antimicrobial and water repellent/ hydrophobic (easy-cleaning) properties on cotton fabrics using nanocoating processes

Baykara, Tarık (Dogus Author) -- Karcı, Yağmur (Dogus Author) -- Rüya Yurttaş (Dogus Author) -- Ayşen Tulpar (Dogus Author) -- Demirural, Alparslan (Dogus Author)Recently, there has been considerable interest in doing research and development on functional nano coated textiles and in creating innovative textile products. Studies have been continued for developing innovative high value-added textile products with antimicrobial, hydrophobic (water and stain repellent), hydrophilic “easy-cleaning” and UV resistant properties. The aim of this work is to impart antimicrobial and hydrophobic properties to raw cotton fabrics via functional nano coating processing techniques. Nano silver particles synthesized from silver nitrate (AgNO3) and sodium citrate (Na3C6H5O7) are impregnated into raw cotton fabrics to develop antimicrobial properties. To investigate the antimicrobial activity of the treated cotton fabric, E. Coli bacteria tests have been performed. Coating the raw cotton fabric with methyltriethoxysilane (CH3Si(OC2H5)3), phenyltrimethoxysilane (C6H5Si(OCH3)3), and alcosols synthesized from these two compounds using sol gel techniques, produced hydrophobic surfaces. Contact angle measurements and easy-cleaning tests are performed on these surfaces