Investigation of forestry wastes: Torrefaction and their thermal properties for use in energy recovery schemes

Three biomasses like Eucalyptus, Azadirachata, and Ficus religiosa were torrefied to investigate the effect of temperature and residence time was investigated on torrefied biomasses for yield, volatile matter, fixed carbon, ash, and Gross calorific value (GCV). Thermogravimetric analysis and Hardgrove grindability index (HGI) of three torrefied samples were studied at optimum conditions of temperature and residence time. According to the results, an optimum temperature was found to be 260°C at 45 min residence time. A maximum GCV of torrefied biomasses of Eucalyptus, Azadirachata, and F. religiosa were found to be 4,301, 3,190, and 3,278 kcal/kg, respectively. According to thermogravimetric analyzer results, the Azadirachata has shown higher weight loss compared to Eucalyptus and F. religiosa during thermogravimetirc study. The weight loss rate for Azadirachata was maximum to nearly 12.8%/min compared to 6.11 and 5.12%/min for Eucalyptus and F. religiosa, respectively. The order of reactivity based on mean reactivity and combustion characterization factor was found to be Azadirachata indica > Eucalyptus > F. religiosa. According to HGI results, Eucalyptus, Azadirachata, and F. religiosa have shown HGI values of 71, 60.7, and 81.7, respectively. The results of this study could be useful for the energy recovery schemes in the country.     

Study on microstructure,rheological, and mechanical properties of cellulose short fiber reinforced TPVs based on EPDM/PP

The morphology, rheology, and mechanical properties of the dynamically vulcanized thermoplastic elastomer based on EPDM/PP (60/40, w:w) containing 5, 10, and 20% of cellulose short fiber were studied. From the results it was found that addition of 5% of cellulose fiber has no significant effect on the maximum torque associated with the dynamic vulcanization stage, while higher concentration of fibers decreased the maximum torque. These results were explained in terms of influence of cellulose fibers on the extent of agglomeration formed between the cured rubber particles. The results of tensile test performed on the samples showed that incorporation of 5% of cellulose fibers into the sample has an increasing effect on elongation at break with no appreciable change in tensile behavior. However increasing the cellulose fibers content of the sample to 20% had a remarkable change in tensile properties of the sample resulting in a toughened plastic type behavior. The melt elasticity of the sample containing 5% of cellulose fibers particularly at low shear rate range was found to be lower than that of the sample without fibers indicating the role of fibers in weakening of cured rubber particle agglomeration. This was supported with the results of the relaxation time distribution H(λ) and scanning electron microscopy of the samples. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Physiochemical characterizations of nanobelts consisting of three mixed oxides (Co<Subscript>3</Subscript>O<Subscript>4</Subscript>, CuO,and MnO<Subscript>2</Subscript>) prepared by electrospinning technique

In this work, nanobelt mats consisting of three potential metal oxides have been produced using the electrospinning technique. An aqueous solution of cobalt acetate tetra-hydrate, copper acetate mono-hydrate, and manganese acetate tetra-hydrate was mixed with poly(vinyl alcohol) solution to prepare a sol–gel which was electrospun at 20 kV. The obtained nanofiber mats have been vacuously dried at 80 °C for 24 h and then calcined in air atmosphere at different temperatures and soaking times. The utilized physiochemical characterizations have affirmed that nanobelts composed of three oxides (Co₃O₄, CuO, and MnO₂) can be prepared by calcination at a temperature of 600 °C for 1 h. High-resolution transmission electron microscope and selected area electron pattern images revealed good crystallinity for the synthesized nanobelts.     

Novel amorphous precursor densification to transparent Nd:Y2O3 Ceramics

A novel approach of neodymium ion doped yttrium oxide (Nd:Y₂O₃) amorphous precursor compaction and sintering is being reported for the first time. Precursor of 2 at.% Nd³⁺ doped Y₂O₃ was synthesized by gelation of sol of yttrium and neodymium nitrates with l-alanine at 80 °C for 16 h followed by gel combustion in microwave. A part of microwave precursor was heat treated at 700 °C for 5 h to give the partially crystalline Nd:Y₂O₃ amorphous precursor. Thermogravimetric analysis (TGA) of partially crystalline amorphous precursor of Nd:Y₂O₃ gave 8.5% total weight loss indicating removal of maximum organics. X-Ray diffraction (XRD) showed broad peaks indicating incomplete crystallization of cubic Nd:Y₂O₃. Morphology was found to be close to spherical with particles in size range 17–19 nm by TEM. Another part of microwave precursor on calcination at 1000 °C for 3 h led to formation of fully crystalline Nd:Y₂O₃ with particles in size range of 35–85 nm. Both partially crystalline amorphous precursor and fully crystalline Nd:Y₂O₃ were compacted at 400 MPa by cold isostatic press and sintered at 1750 °C for 10 h under vacuum (10^?5 mbar). The partially crystalline Nd:Y₂O₃ amorphous precursor densified to 99% with 65% transmission at 2500 nm (0.5 mm thickness) compared to 96% densification with 34% transmission for fully crystalline Nd:Y₂O₃ without any sintering aids. Retention of cubic phase purity of Y₂O₃ was observed in both the ceramic pellets post sintering by XRD. Good grain fusion with grain growth to ≤2 μm was observed by scanning electron microscope (SEM) for partially crystalline Nd:Y₂O₃ amorphous precursor. Thus partially crystalline Nd:Y₂O₃ amorphous precursor nanopowders, with homogeneous close to spherical fine particles and high reactivity due to ionic mobility of amorphous phase, led to better densification.     

Ring-Shaped Lateral Bracing System for Steel Structures

Buckling of compression members has a great impact on the reduction of energy dissipation capacity and ductility of the structural system such as concentrically braced frame systems (CBFs). As well, direct connection of tensile and compression members to beams and designation of the link beam as a fuse, and the formation of plastic hinges in the link beam in eccentrically braced systems (EBFs) endanger the safety of this type structural systems. This paper introduces a new ring-shaped lateral bracing system so-called the Shami lateral bracing system (SLBs) which removes the common tensile and compressive members along with their connections to the structure. As a substitute, SLBs introduces a new element with proper ductility and energy dissipation capacity and could be an appropriate alternative to the existing systems. Because of the high degree of statically indeterminacy of the proposed system, the structural stiffness does not lead to a steep reduction after the formation of the first plastic hinge. The performance of this lateral system is evaluated by numerical modeling, and the results show that the structures resist against the lateral loads with acceptable seismic performance. It seems that this system in comparison with CBF and EBF systems may not be cost-effective for bending of the ring, welding, etc., but from the seismic performance points of view, it has good performance.     

Effect of camel milk protein hydrolysates against hyperglycemia,hyperlipidemia, and associated oxidative stress in streptozotocin (STZ)-induced diabetic rats

This study investigated the effect of camel milk protein hydrolysates (CMPH) at 100, 500 and 1,000 mg/kg of body weight (BW) for 8 wk on hyperglycemia, hyperlipidemia, and associated oxidative stress in streptozotocin-induced diabetic rats. Body weights and fasting blood glucose levels were observed after every week until 8 wk, and oral glucose tolerance test (OGTT) levels and biochemical parameters were evaluated after 8 wk in blood and serum samples. Antioxidant enzyme activity and lipid peroxidation in the liver were estimated, and histological examination of the liver and pancreatic tissues was also conducted. Results showed that CMPH at 500 mg/kg of BW [camel milk protein hydrolysate, mid-level dosage (CMPH-M)] exhibited potent hypoglycemic activity, as shown in the reduction in fasting blood glucose and OGTT levels. The hypolipidemic effect of CMPH was indicated by normalization of serum lipid levels. Significant improvement in activity of superoxide dismutase and catalase, and reduced glutathione levels were observed, along with the attenuation of malondialdehyde content in groups fed CMPH, especially CMPH-M, was observed. Decreased levels of liver function enzymes (aspartate aminotransferase and alanine aminotransferase) in the CMPH-M group was also noted. Histology of liver and pancreatic tissue displayed absence of lipid accumulation in hepatocytes and preservation of β-cells in the CMPH-M group compared with the diabetic control group. This is the first study to report anti-hyperglycemic and anti-hyperlipidemic effect of CMPH in an animal model system. This study indicates that CMPH can be suggested for its therapeutic benefits for hyperglycemia and hyperlipidemia, thus validating its use for better management of diabetes and associated comorbidities.     

Sulfur removal of gas oil using ultrasound-assisted catalytic oxidative process and study of its optimum conditions

Ultrasound-assisted oxidative desulfurization process (UAOD) was applied to reduce sulfur compounds of gas oil containing various types of sulfur content. The environmental regulation requires a very deep desulfurization to eliminate the sulfur compounds. UAOD is a promising technology with lower operating cost and higher safety and environmental protection. For the first time the typical phase transfer agent (tetraoctyl-ammonium-bromide) was replaced with isobutanol because using isobutanol is much more economical than TOAB, imposing no contamination. The reaction was carried out at optimal point with various temperatures, in single-, two- and three step-procedures, investigating the effect of gradual increase of H₂O₂ and TOAB being used instead of isobutanol. Total sulfur concentration in oil phase was analyzed by ASTM-D3120 method. The highest removal of about 90% for gas oil containing 9,500 mg/kg of sulfur was achieved in three-steps during 17 minutes of process at 62±2 °C when 180.3 mmol of H₂O₂ was used and extraction carried out by methanol.     

The effect of EEMAO processing on surface mechanical properties of the TiO2–ZrO2 nanostructured composite coatings

We report fabrication of TiO₂–ZrO₂ nanostructured composite coatings by EPD-Enhanced MAO (EEMAO) technique on titanium substrates where especial emphasis was placed on improving the surface hardness of the substrates and establishing a microstructure-property correlation. Based on the XRD and the EDX results, the layers consisted of anatase, rutile, monoclinic zirconia, and tetragonal zirconia. It was observed that the anatase/rutile and tetragonal/monoclinic zirconia rations increased with the processing time and the electrolyte concentration. The zirconia content also increased with the processing time and the electrolyte concentration. XPS technique was also employed to further confirm the surface chemical composition and stoichiometry of the layers. A uniform distribution of zirconia across the titania matrix was evident in the SEM images. The surface hardness of the TiO₂-ZrO₂ composite layers was observed to increase with the zirconia concentration. Employing EEMAO technique, the surface harness of the titanium substrates was successfully improved from ∼190 Hv to ∼700 Hv.     

Accelerated Mold Test on Dried Pine Sapwood Boards: Impact of Contact Heat Treatment

Abstract

We test the hypothesis that the combination of kiln drying of double-stacked boards and contact heat treatment will reduce the susceptibility of treated boards to colonization by mold fungi. Winter-felled Scots pine (Pinus sylvestris L.) sapwood boards were double-stacked in an industrial kiln in ‘‘sapwood out’’ and ‘‘sapwood in’’ positions. Dried samples were then contact heat-treated using a hot press at three different temperatures (140°C, 170°C, and 200°C) for three different periods (1, 3, and 10 min). An accelerated mold test was performed in a climate chamber where naturally mold-infected samples were used as a source of mold inocula. Contact heat treatment degraded the saccharides that accumulated at dried surfaces, and reduced the mold growth. The threshold temperature and time for inhibiting mold growth were 170°C for 10 min. However, for industrial application, the most feasible combination of temperature and time would be 200°C for 3 min. We concluded that double stacking/contact heat treatment used is an environmentally friendly alternative to chemicals for reducing mold on Scots pine sapwood boards.