Solid waste processing for industrial utilization— a few case studies

The production of low grade materials as waste during mining and processing operations is highlighted. The need for utilization of such materials for conservation and sustainability of mineral resources is explained. The case studies of three solid waste materials—Manganese dump ores, Sericitic Pyrophyllite and Rice Husk Ash is presented. Their characterization, processing and end-use application has been enumerated in detail to establish the fact that judicious processing can lead to sustainable resource utilization

Immobilization of Metal Sulfide Nanocrystals on Multiwalled Carbon Nanotubes Facilitated by Infrared Irradiation

Uniformly distributed metal sulfide nanocrystals are immobilized on the surface of oxygenated multiwalled carbon nanotubes (MWCNTs) by reacting metal ions (Cu 2+ / Zn 2+ /Cd 2+ ) anchored to MWCNTs with hydrogen sulfide while irradiating with infrared (IR) radiation. The IR irradiation is the key step in the effective immobilization of metal sulfide nanocrystals on MWCNTs. The photoabsorption and photothermal properties of MWCNTs in the presence of IR irradiation raises the temperature of the CNTs in solution, facilitating the interaction between the acidic groups on CNTs and the metal ions, which results in effective immobilization of the nanocrystals. The metal sulfide-MWCNT hybrids are characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy

Manufacturing, Evaluation and Field Implementation of Recycled GFRP-Composite Railroad Ties

Wood railroad crossties resistance to current higher axle loads, speeds and frequency, along with the durability under harsh environments has proven to be inadequate. Additionally, defects such as decay, holes, splits, checks etc may further impair the strength and durability characteristics of the wood crossties. In this project, recycled polymer and discarded wood were used to increase the performance characteristics of the RR tie including resistance to higher axle loads, minimization of defects, and better performance under harsh environmental conditions. The objective of this study is to enhance and assess the strength characteristics of the timber crossties by using the glass fiber reinforced polymer (GFRP) composite shell. This research involved two different techniques for manufacturing the recycled composite ties, followed by laboratory testing of wood ties and GFRP recycled composite shell with wood core ties (thermoplastic) in WVU-CFC. The previous research program at WVU-CFC consisted of strengthening and evaluating the wood crossties by wrapping only the 12 inches wide steel plate embedment location using glass fiber fabrics saturated with resorcinol formaldehyde resin (thermoset).;In this research, over 200 recycled composite components were manufactured in the CFC laboratory that were used to mold 24 full-scale recycled composite ties with wood as a core material and GFRP composite as a shell material. The GFRP composite shell was manufactured using glass fabric reinforcement and Acrylonitrile Butadiene Styrene (ABS) resin. Two different fiber configurations were used in the manufacturing process-I (composite ties manufactured using twelve composite parts). Recycled composite ties produced under manufacturing process-I were tested under three point bending to evaluate the flexural rigidity. Test results of recycled composite ties from manufacturing process-I having fabric configuration-I were compared with those having fabric configuration-II. Further, recycled composite tie from manufacturing process-II (composite ties manufactured using two composite parts) along with wood crossties were tested under three point bending to evaluate the flexural rigidity, modulus of rupture, and static bending strength. Recycled composite ties showed higher static bending strength by approximately sixty percent than wood ties. Recycled composite ties also showed higher spike insertion and pullout strengths than the wood ties.;In order to study the dynamic response, a full-scale recycled composite tie produced through manufacturing process-II was embedded in gravel ballast and tested under flexural fatigue. The measured maximum deflection and applied bending moment values were compared with the theoretical values based on the classical beams on elastic foundation theory. The theoretical values were found to correlate well with the experimental values (within 10%). The research also included field testing of seven recycled composite ties on the South Branch Valley Railroad (SBVR) in Moorefield, WV. After three months of service, three ties with low fiber/fabric content showed localized horizontal cracking or some transverse cracks and the remaining four ties showed good field performance. Additional ties manufactured under this project are planned to be field-tested at TTCI, Pueblo, Colorado, test facilities. Conclusions and recommendations from this research work are summarized at the end of this report

Drag and inertia coefficients for horizontally submerged rectangular cylinders in waves and currents

The results of an experimental investigation carried out to measure combined wave and current loads on horizontally submerged square and rectangular cylinders are reported in this paper. The wave and current induced forces on a section of the cylinders with breadth-depth (aspect) ratios equal to 1, 0.5, and 0.75 are measured in a wave tank. The maximum value of Keulegan-Carpenter (KC) number obtained in waves alone is about 5 and Reynolds (Re) number ranged from 6.3976103 to 1.186105. The drag (CD) and inertia (CM) coefficients for each cylinder are evaluated using measured sectional wave forces and particle kinematics calculated from linear wave theory. The values of CD and CM obtained for waves alone have already been reported (Venugopal, V., Varyani, K. S., and Barltrop, N. D. P. Wave force coefficients for horizontally submerged rectangular cylinders. Ocean Engineering, 2006, 33, 11-12, 1669-1704) and the coefficients derived in combined waves and currents are presented here. The results indicate that both drag and inertia coefficients are strongly affected by the presenceof the current and show different trends for different cylinders. The values of the vertical component inertia coefficients (CMY) in waves and currents are generally smaller than the inertia coefficients obtained in waves alone, irrespective of the current's magnitude and direction. The results also illustrate the effect of a cylinder's aspect ratio on force coefficients. This study will be useful in the design of offshore structures whose columns and caissons are rectangular sections

Magnetohydrodynamic Flow Past a Permeable Bed

The paper evaluates mass flow velocity heat transfer rates and velocity/temperature distributions in the viscous, incompressible and slightly conducting fluid past a permeable bed in three different configurations namely (1) Couette flow (2) Poiseuille flow and (3) free surface flow, under the influence of a uniform transverse magnetic field. To discuss the solution, the flow region is divided into two zones : Zone 1 (from the impermeable upper rigid plate to the permeable bed) in which the flow is laminar and governed by Navier-Stokes equations, and Zone 2 (the permeable bed below the nominal surface) in which the flow is governed by Darcy law. The paper also investigates the effects of magnetic field, porosity and Biot number on the physical quantities mentioned above