Grain Drying in a Paraboloid-Based Spouted Bed with and without Draft Tube

In this study, grain drying in a spherical-based spouted bed (SBSB), a cone-based spouted bed (CBSB), and a paraboloid-based spouted bed (PBSB) with and without draft tube was investigated. Spouted-bed bases with the same volume in different shapes—spherical, cone, and paraboloid—were used for the drying experiments to investigate the effect of the spouted-bed base shape on drying. The drying experiments were carried out with perforated and solid draft tubes. The effects of the distance between the gas inlet nozzle and the bottom of the draft tube (entrainment zone height) and the draft tube diameter as geometric parameters on drying were also investigated. It was seen that the geometrical shape of the contactor base influenced the drying time. The highest drying rate was achieved for drying in a paraboloid-based spouted bed. The results also showed that using a draft tube caused a significant increase in drying time. Because the perforated draft tube allows a higher gas flow rate through the annulus, it decreases the drying time when compared with the solid draft tube. Drying time decreased slightly with the decreasing height of the entrainment zone but draft tube diameter did not have a considerable effect on drying.     

Biosorption of Pb(II) ions from aqueous solution by pine bark (Pinus brutia Ten.)

The biosorption potential of pine (Pinus brutia Ten.) bark in a batch system for the removal of Pb(II) ions from aqueous solutions was investigated. The biosorption characteristics of Pb(II) ions on the pine bark was investigated with respect to well-established effective parameters including the effects of solution pH, initial Pb(II) concentration, mass of bark, temperature, and interfering ions present, reusability, and desorption. Initial solution pH and contact time were optimized to 4.0 and 4 h, respectively. The Langmuir and Freundlich equilibrium adsorption models were studied and observed to fit well. The maximum adsorption capacity of the bark for Pb(II) was found to be 76.8 mg g⁻¹ by Langmuir isotherms (mass of bark: 1.0 g L⁻¹). The kinetic data fitted the pseudo-second-order model with correlation coefficient greater than 0.99. The thermodynamic parameters Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) changes were also calculated, and the values indicated that the biosorption process was spontaneous. Reutilization of the biosorbent was feasible with a 90.7% desorption efficiency using 0.5 M HCl. It was concluded that pine bark can be used as an effective, low cost, and environmentally friendly biosorbent for the removal of Pb(II) ions from aqueous solution.     

Effect of titania and zinc oxide particles on acrylic polyurethane coating performance

The outer environment, especially UV portion of solar radiation and water (in the form of moisture or rain) has an adverse effect on the surface appearance of heat-treated wood. Exposure to UV triggers the chain scission reactions which change the intrinsic properties of heat-treated wood and discoloration of wood surface. Repeated temperature and humidity variations cause swelling and shrinking of wood surface, which consequently create cracks and fissures exposing wood's sub superficial layers to atmospheric agents. Therefore, wood industries move towards the development of coatings in order to protect the heat-treated wood while retaining wood's natural look. Water based acrylic polyurethane coatings are highly efficient, non toxic and durable coatings with upgraded film properties. In this study, an attempt is made to improve the performance of these coatings by incorporating natural antioxidant (bark extract) and inorganic UV absorbers (nano and micro titania and nano zinc oxide) into the coatings. The main objectives of this study are to investigate the wetting and penetration characteristic of these new coatings on the wood surface and to study coating thickness variation with weathering time. The Sessile-drop method and fluorescence microscope are used for this investigation. The wettability of different coatings applied to heat-treated jack pine early wood and late wood is compared. The results show that there is a significant difference between the contact angle of early wood and late wood for acrylic polyurethane coating containing titania micro particles. The contact angle between water and coated wood surface reveals that the degree of orientation of the coating materials increases as the weathering time increases. The penetration characteristics of all the four coatings are found to be very poor. In addition, the relationship between the coating thickness and the UV exposure time is studied for four water based acrylic polyurethane coatings with different additives. It is found that the coating thickness decreases with increasing weathering time and a tissue deformation beneath the coating surface takes place during weathering.     

Polymerization and characterization of various di(pyridine)bis(trihalophenolato)cobalt(II) complexes in solid and melt states

The syntheses of distorted tetrahedral bis(pyridine)bis(trihalophenolato)cobalt(II) complexes from an aqueus solution were achieved and their characterization by FT‐IR, X‐ray, DSC, UV‐visible and elemental analysis in solid state or in melt form is reported. Polymerizations of these complexes were accomplished either at constant temperature, employing different time intervals or constant decomposition times while varying the temperature range. The slow decomposition at constant temperature leads to long chain products, whereas long chains formed at higher temperatures were during a constant time. The resulting poly(dihalophenylene oxide)s were characterized by FT‐IR, ¹H NMR, ¹³C NMR spectral analysis, differential scanning calorimetry and molecular weight determinations by viscometric method. © 2001 Society of Chemical Industry     

Investigation of the thermostability of poly(ethylene terephthalate)–hemp fiber composites: Extending natural fiber reinforcements to high‐melting thermoplastics

The thermal stability of poly(ethylene terephthalate) reinforced with 1, 5, 10, 15, and 20% hemp fibers was investigated with the aim of extending the applications of biocomposites to high‐melting thermoplastics. The material was injection‐molded following compounding with a torque‐based Rheomix at 240, 250, and 260°C. A combination of thermogravimetric methods at 5, 10, and 20°C/min, Liu and Yu's collecting temperature method, and Friedman's kinetic method were used for testing and analysis. A significant thermostability for all formulations was observed below 300°C; this demonstrated their potential for successful melt processing. Moreover, two degradation steps were observed in the temperature ranges 313–390 and 390–490°C. The associated apparent activation energies within the temperature ranges were determined as 150–262 and 182–242 kJ/mol, respectively. We found that the thermostability was significantly affected by the heating rates; however, the effect of the temperature of the mixing chamber was negligible. These findings suggest that the successful melt processing of high‐melting thermoplastics reinforced with natural fibers is possible with limited fiber thermodegradation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42500.     

Preparation of land use planning model using GIS based on AHP: case study Adana-Turkey

An environmental and earthquake sensitive planning approach requires a suitability evaluation based upon geo-environmental analysis before the planning phase. In land use evaluation analysis the local data from different disciplines must be synthesized as the priority and importance of the geo environmental criteria change according to the use of the site. Geographical information systems (GIS) using multiple criteria methods allow the determination of priorities and the importance of local/non-local data for the most efficient use of land. In this study six land use categories of Adana, one of the most earthquake prone provinces of Turkey, were determined by the use of an analytical hierarchical process (AHP) and GSI. These are high rise blocks, multi storey buildings, low storey buildings, industrial sites, waste disposal sites and green land.     

Metal‐ion‐containing ionic liquid hydrogels and their application to hydrogen production

A cationic hydrogel synthesized from (3‐acrylamidopropyl) trimethyl ammonium chloride as poly[(3‐acrylamidopropyl) trimethyl ammonium chloride] [p(APTMACl)] was put into contact with the chloride salts of metals such as CoCl₂, NiCl₂, and CuCl₂ in ethanol. The metal‐loaded p(APTMACl) hydrogels were used as catalyst systems in hydrogen generation from the hydrolysis of sodium borohydride (NaBH₄) and ammonia borane. The activation energy values for the hydrolysis reaction were calculated for all of the catalyst systems and were found to be 53.43 and 26.74 kJ/mol for p(APTMACl)–[CoCl₄]^2? and p(APTMACl)–[NiCl₄]^2?, respectively. These activation parameters were better than values reported in the literature for the ionic liquid metal complexes of smaller molecules used for the same purpose. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40183.     

Synthesis of bulk nanocrystalline HfB<Subscript>2</Subscript> from HfCl<Subscript>4</Subscript>–NaBH<Subscript>4</Subscript>–Mg ternary system

This study reports on the synthesis and consolidation of pure HfB₂ powders starting from HfCl₄–NaBH₄–Mg blends via autoclave processing, annealing and purification followed by pressureless sintering (PS, with 2 wt% Co aid) or spark plasma sintering (SPS). During autoclave reactions conducted at 500 °C for 12 h under autogenic pressure, excess amounts of NaBH₄ were utilized to investigate its effects on the reaction products and mechanism. A subsequent washing (with distilled water), annealing (at 750, 1000 and 1700 °C) and acid leaching (HCl) were applied on the as-synthesized products. Pure HfB₂ powders with an average particle size of 145 nm were obtained after autoclave synthesis in the presence of 200 wt% excess NaBH₄, washing, annealing at 1000 °C for 3 h and 6 M HCl leaching. SPS sample has higher relative density and microhardness values (94.18% and 20.99 GPa, respectively) than those of PS sample (90.14% and 14.85 GPa). Relative wear resistance was improved considerably (8.2 times) by employing SPS technique.