Coating of modified poly(ethylene terephthalate) fibers with sericin-capped silver nanoparticles for antimicrobial application

Polymer Bulletin - In this work, a kind of amine-type PET fibers was synthesized by reacting hexamethylenediamine (HMDA) with methacrylic acid-g-poly(ethylene terephthalate) (PET-g-MAA) fibers for...     

Toward the development of an innovative descaling and corrosion inhibiting solutions to protect mild steel equipment: an experimental and theoretical approach

Abstract

This work proposes a mixture of sulfamic and perchloric acids as a descaling solution and cetyltrimethyl ammonium bromide (CTAB) and imidazole for the improvement in the corrosion resistance of mild steel. The experiments were carried out at different temperatures using mass loss and electrochemical techniques. The samples were characterized by inductively coupled plasma spectrometry, SEM-EDS, and X-ray diffraction techniques. The study showed that CTAB and imidazole can serve as the efficient corrosion inhibitors for mild steel in descaling solution and were found to follow the model of Langmuir adsorption isotherm. Potentiodynamic polarization was performed at temperature 295, 305, 315, and 325?K, and it can be concluded that the CTAB/imidazole acted as mixed type corrosion inhibitors. Electrochemical impedance spectroscopy studies revealed that increase in imidazole concentration, resulted into the increased polarization resistance with simultaneous lowering of double-layer capacitance values. Computational techniques were used to support experimental results.     

Effects of welding procedures on mechanical and morphological properties of hot gas butt welded PE,PP, and PVC sheets

Mechanical and morphological properties of hot gas butt welds on polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC) sheets for four different procedures, which are single and double V‐welds with and without a welding shoe, were investigated. Besides, weldabilities of base materials were evaluated by rheological measurements. These revealed that weldabilities of PE and PP sheets were better than that of PVC. Welding energy (E_w), which is transferred onto weld surfaces, was calculated to evaluate weld quality. The results of tensile, impact, and bending tests indicated that the weld strengths of PVC sheets were lower than those of PE and PP sheets. When the welding shoe was used, weld strength increased significantly for each material because of the presence of sufficient welding pressure and the effective heating on surfaces. The best results were attained for the double V‐welds with the welding shoe. Morphology of welded regions was evaluated by polarized light, stereo, and scanning electron microscopy. Polarized light microscopy studies indicated that the heat‐affected zone (HAZ) consisted of welding rod core, molten zone, and deformed spherulitic zone, and the welding interface was indistinguishable from the base material when the welding pressure was enough. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Effects of scarf joints on bending strength and modulus of elasticity to laminated veneer lumber (LVL)

The role of geometry on the mechanical performance of scarf joints in laminated veneer lumber (LVL) bonded with phenol formaldehyde and melamine formaldehyde (MF) adhesives was investigated. Model joints consists of 3, 4 and 5 mm veneer thicknesses at 30°, 45° and 60° of varying scarf joints for LVL produced from brutia pine (Pinus brutia Ten) and elm (Ulmus compestris l.) woods. However, there is little information available concerning the bending strength and modulus of elasticity for LVL, and in particular, scarf joints in these field. In this study, it was aimed to determine the bending strength and modulus of elasticity for LVL. For this purpose, samples were tested according to TS EN 310 standard. It was observed that the highest bending strength (291.5 N/mm²) and modulus of elasticity (28 101 N/mm²) were obtained in control (solid wood) samples having three layered LVL, jointed with 30° angle and bonded with MF adhesive. As a result of the effects scarf joints on bending strength and modulus elasticity test, if the scarf angle decreases, the properties of LVL increase.     

Design of a PEM fuel cell system for residential application

Fuel cells are energy transformation technologies and they are clean, don't damage to environment, have high efficiency and provide uninterruptible energy generation. Research and development studies about fuel cells have been done increasingly. In the recent years, fuel cell technologies have performed in some sectors such as military, industrial, space, portable, residential, transportation and trading.     

Engineering Perspective of the Collapse of WTC-I

The writers report on a simulation study of the performance of the North Tower (WTC-I) of the World Trade Center complex during the impact of American Airlines Flight 11 on September 11, 2001. We discuss impact damage that the structural core might have sustained and its possible behavior under structural and thermal loading. Our simulations indicate that the worst damage to the core structure was in stories 95 through 97 of the tower. We estimate that a core collapse mechanism could be initiated if the tower core column temperatures were elevated to about 700°C.     

Assessment of power and hydrogen production performance of an integrated system based on middle-grade geothermal source and solar energy

In this study, power and hydrogen production performance of an integrated system is investigated. The system consists of an organic Rankine cycle (ORC), parabolic trough solar collectors (PTSCs) having a surface area of 545 m², middle-grade geothermal source (MGGS), cooling tower and proton exchange membrane (PEM). The final product of this system is hydrogen that produced via PEM. For this purpose, the fluid temperature of the geothermal source is upgraded by the solar collectors to drive the ORC. To improve the electricity generation efficiency, four working fluids namely n-butane, n-pentane, n-hexane, and cyclohexane are tried in the ORC. The mass flow rate of each working fluid is set as 0.1, 0.2, 0.3, 0.4 kg/s and calculations are made for 16 different situations (four types of working fluids and four different mass flow rates for each). As a result, n-butane with a mass flow rate of 0.4 kg/s is found to be the best option. The average electricity generation is 66.02 kW between the hours of 11⁰⁰-13⁰⁰. The total hydrogen production is 9807.1 g for a day. The energy and exergy efficiency is calculated to be 5.85% and 8.27%, respectively.     

HYDROGEN RESOURCES : CONVERSION OF BLACK LIQUOR TO HYDROGEN RICH GASEOUS PRODUCTS

Abstract

Two precipitates were obtained from original black liquor by using hydrochloric acid and carbon dioxide. The precipitates were liqufied and gasificated by non-catalytic and catalytic runs at gradually elevated temperatures. The amount of gaseous products increased with increasing temperature and percent of catalyst. The percent of hydrogen in the obtained gas mixture was the highest in potassium carbonate catalytic runs (37 %).