254 results on '"Cumaraswamy Vipulanandan"'
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202. Coatings for concrete surfaces
- Author
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J. Liu and Cumaraswamy Vipulanandan
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Cement ,chemistry.chemical_classification ,Chemical resistance ,Materials science ,Coating materials ,Sulfuric acid ,Polymer ,Epoxy ,chemistry.chemical_compound ,Hydrostatic test ,chemistry ,visual_art ,visual_art.visual_art_medium ,Composite material ,Polyurethane - Abstract
Publisher Summary This chapter presents a combination of test methods and models to predict mass change and pinhole effect for coated concrete. It discusses test and analytical results for epoxy and polyurethane coatings. A series of full-scale and laboratory tests are developed to evaluate the performance of coating materials for protecting dry and wet concrete substrates exposed to sulfuric acid environments. Commercially available polymer and cement-based coatings are studied for a period of over five years. Analytical models are developed to predict mass change and holiday size effect on coated concrete. The performance of epoxy coated concrete in de-ionized (D.I.) water and 3% sulfuric acid is investigated. The chapter provides observations based on the experimental results and analyses. The full-scale hydrostatic test was used to evaluate the applicability of coatings onto concrete and two bonding tests were modified, based on the ASTM standards. Chemical resistance tests can evaluate the acid resistance of coated concrete. The film model and concrete model can be used to predict mass increase of coated concrete in reactive and non-reactive solutions. more...
- Published
- 2005
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203. Development and Characterization of Piezoresistive Smart Structural Materials
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Kallol Sett and Cumaraswamy Vipulanandan
- Subjects
Materials science ,Structural material ,Nanotechnology ,Piezoresistive effect ,Characterization (materials science) - Published
- 2004
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204. Properties of Polyester Polymer Concrete with Glass and Carbon Fibers
- Author
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Cumaraswamy Vipulanandan and Kallol Sett
- Subjects
All-silica fiber ,Materials science ,Glass fiber ,Polymer concrete ,Building and Construction ,Poisson's ratio ,Polyester ,symbols.namesake ,symbols ,General Materials Science ,Fiber ,Composite material ,Hard-clad silica optical fiber ,Civil and Structural Engineering - Published
- 2004
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205. CIGMAT Testing Programs for Coatings/Linings, Grouts and Pipe-Joints in Sewers
- Author
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Cumaraswamy Vipulanandan and J. Liu
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Pipeline transport ,Materials science ,Coating ,Grout ,Hydrostatic pressure ,Coating materials ,engineering ,Full scale ,Geotechnical engineering ,Sanitary sewer ,engineering.material ,Composite material ,Durability - Abstract
The testing programs were developed to evaluate the performance of coating, lining and grouting materials used in the rehabilitation of wastewater facilities and to quantify the infiltration at pipe joints using a combination of full scale and laboratory tests. For the coating/lining testing program, special testing chambers are available to verify the applicability of various coating materials to concrete pipe under a hydrostatic pressure of 105 kPa (15 psi). To quantify the bonding strength between the coatings and substrates (concrete and clay bricks) several ASTM/CIGMAT test methods are being used. A control test with Holidays has been developed to quantify the chemical resistance of coated materials to acidic environment. Based on the test results, it will be possible to develop relationships and quantify the effectiveness of various coating/lining materials. A combination of grout, grouted sand and model tests are being used to evaluate grouts for leak control at pipe/manhole joints, service connections and cracks. Grouts are being characterized using the working, physical, mechanical and durability properties. more...
- Published
- 2003
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206. Wet-Dry Cyclic Behavior of a Hydrophilic Polyurethane Grout
- Author
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Steve Hennings, Cumaraswamy Vipulanandan, Y. Mattey, and David Magill
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chemistry.chemical_compound ,Materials science ,chemistry ,Grout ,engineering ,Composite material ,engineering.material ,Polyurethane - Published
- 2003
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207. Testing a Polymer Concrete Coating for Dry and Wet Concrete and Clay Brick Wastewater Facilities
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Cumaraswamy Vipulanandan and J. Liu
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Hydrostatic test ,Materials science ,Coating ,Wastewater ,engineering ,Clay brick ,Polymer concrete ,engineering.material ,Composite material - Published
- 2003
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208. Axial Performance of ACIP Piles in Texas Coastal Soils
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Alaa Ata, Cumaraswamy Vipulanandan, Stanley Yin, and Michael W. O'Neill
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geography ,Drilled shaft ,geography.geographical_feature_category ,Terrace (geology) ,Water table ,Alluvial soils ,Soil water ,Drilling ,Geotechnical engineering ,Geology - Abstract
Methods were evaluated for assessing axial compressive capacities of augered, cast-inplace (ACIP) piles in the Pleistocene terrace deposits of the Texas Gulf Coast and Recent to Modern alluvial soils. The study involved a combination of data base analyses and the performance of new loading tests on instrumented piles. The results in sand deposits mirrored earlier studies that indicated that common methods used for designing drilled shafts are also appropriate for ACIP piles, although the patterns of load transfer in the tested piles suggested zones of both lower load transfer (running sands below the water table) and higher load transfer (compacted surface soils) than would be expected in drilled shafts. The action of drilling and grouting resulted in net increases in lateral effective stresses in the soil around the tested piles, near the ground surface, where such measurements were made. In overconsolidated clays, slightly higher unit side resistances were inferred for ACIP piles than are predicted by common drilled shaft design methods. However, common drilled shaft design methods, notably the FHWA method, produced generally accurate capacities for mixed soil profiles. more...
- Published
- 2002
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209. Expansive Clay Soils and Vegetative Influence on Shallow Foundations
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Michael Hansen, Cumaraswamy Vipulanandan, and Marshall B. Addison
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Moisture ,Shallow foundation ,Environmental remediation ,Expansive clay ,Soil water ,Foundation (engineering) ,Environmental science ,Geotechnical engineering ,Vegetation ,Soil mechanics - Abstract
Proceedings of geotechnical sessions at the 2001 Annual Civil Engineering Conference, held in Houston, Texas, October 10-13, 2001. Sponsored by the Shallow Foundation and Soil Properties Committee of the Geo-Institute of ASCE. This Geotechnical Special Publication contains 14 papers that discuss the effects of trees and moisture movements on various lightly loaded foundations on expansive clays. Papers review current state of the practice in foundation design, maintenance, and remediation as it relates to vegetative effects and expansive clays on foundations. Topics include: tree root damage to buildings; predicting volume changes in expansive soils resulting from environmental factors including vegetation; drought; expansive clay soil problems and solutions throughout the world; soil-structure interaction; field test program to obtain geotechnical properties; depth of wetting and active zone in expansive soils; slabs on expansive clay with vegetation considerations; volume change coefficient of expansive clay; in-situ modification of active clays for shallow foundation remediation; cracking of pavement due to drying shrinkage; soil suction measurements; and data base on under-slab moisture contents in Texas. more...
- Published
- 2001
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210. Controlled Verification Testing of Sewer Rehabilitation Techniques and Pipe Joints at CIGMAT -- University of Houston
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Cumaraswamy Vipulanandan and J. Liu
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Engineering ,Rehabilitation ,business.industry ,medicine.medical_treatment ,medicine ,Forensic engineering ,business ,Software verification - Published
- 2001
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211. V-Fracture Properties of Polyester Polymer Concrete With Chopped Graphite Fibers
- Author
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Cumaraswamy Vipulanandan and J. Cao
- Subjects
Polyester ,Materials science ,Flexural strength ,Fracture (geology) ,Modulus ,Polymer concrete ,Graphite ,Composite material - Published
- 2001
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212. Fatigue Crack Growth in Polyester Polymer Concrete
- Author
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Cumaraswamy Vipulanandan and S. Mebarkia
- Subjects
Polyester ,Crack closure ,Materials science ,Fracture (geology) ,Polymer concrete ,Paris' law ,Composite material ,Crack growth resistance curve - Published
- 2001
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213. Characterizing the Behavior of a Hydrophilic Polyurethane Grout
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Cumaraswamy Vipulanandan, Don Mack, Y. Mattey, and David Magill
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chemistry.chemical_compound ,Materials science ,chemistry ,Grout ,engineering ,Composite material ,engineering.material ,Polyurethane - Published
- 2000
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214. Properties of Fly Ash-Cement Cellular Grouts for Sliplining and Backfill Applications
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Cumaraswamy Vipulanandan and M. Neelan Kumar
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Cement ,Waste management ,Fly ash ,Geology - Published
- 2000
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215. Designing Flowable Grout Mixes Using Foundry Sand, Clay and Fly Ash
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C. Zhang, Y. Weng, and Cumaraswamy Vipulanandan
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Waste management ,Grout ,Fly ash ,engineering ,Environmental science ,Geotechnical engineering ,engineering.material ,Foundry - Published
- 2000
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216. Mechanical Properties and Chemical Resistance of Auger Grout
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Michael W. O'Neill, Y Weng, and Cumaraswamy Vipulanandan
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Chemical resistance ,Materials science ,Grout ,Weight change ,Modulus ,Hydrochloric acid ,engineering.material ,chemistry.chemical_compound ,Compressive strength ,chemistry ,Fly ash ,Sodium sulfate ,engineering ,Composite material - Abstract
The major constituent in the augered cast-in-place (ACIP) pile is the grout, and hence, understanding the grout behavior is essential. A laboratory study was undertaken to evaluate the working and mechanical properties and chemical resistance of grout mixtures of which one batch was collected from a field project. Grout behaviors of interest were fluidity, setting time, mechanical properties, and chemical resistance. Chemical resistance of the grout mixes was studied by immersing the specimens in sulfuric acid (pH = 4), hydrochloric acid (pH = 4), sodium sulfate (0.5%), and sodium chloride (0.5%) solutions for a period of two years. Use of additional fluidifier and flyash in the grout and their effects on the flow properties and compressive strength on the grout was quantified and compared to the field samples. Variation of compressive strength, modulus and pulse velocity with curing time for the field samples has been quantified. Grout cube strength was higher than the cylinder strength. The ratio of cylinder strength to cube strength varied from 0.89 to 0.93 with an average of 0.91. Increasing the flyash content 25 to 35% did not affect the fluidity or compressive strength of the standard grout. During the two years of immersion test on grouts weight change and the amount of calcium leached from the specimens has been quantified. The weight changed observed varied from -3 to +3% and the maximum calcium leached was 0.5%. Of the solutions studied, 0.5% sodium sulfate solution has the greatest damage on the grout. The data suggests that ACIP piles maybe more susceptible to sulfate attack than concrete piles. more...
- Published
- 2000
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217. Modeling of Laterally Loaded ACIP Piles in Overconsolidated Clay
- Author
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Khaled M. Hassan, Michael W. O'Neill, and Cumaraswamy Vipulanandan
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Cracking ,Engineering ,Shaft mining ,business.industry ,Drilling ,Geotechnical engineering ,Structural engineering ,Pile ,business - Abstract
Cyclic lateral loading tests were performed for the Texas Department of Transportation on a series of augered, cast-in-place (ACIP) piles in over consolidated clay at the National Geotechnical Experimentation Site - University of Houston. Pile diameters and penetrations were varied. A p-y model, modified from the Welch-Reese model developed in similar soils for drilled shafts, was found to give excellent predictions of pile performance, and a simplified hand solution that does not require the use of a computer, was provided prediction of behavior up to the load that produced tensile cracking in test files. more...
- Published
- 2000
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218. Impedance Spectroscopy Characterization of a Piezoresistive Structural Polymer Composite Bulk Sensor
- Author
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P. Prashanth and Cumaraswamy Vipulanandan
- Subjects
Stress (mechanics) ,Materials science ,Mechanics of Materials ,Tension (physics) ,Mechanical Engineering ,Ultimate tensile strength ,Contact resistance ,General Materials Science ,Bending ,Composite material ,Compression (physics) ,Piezoresistive effect ,Dielectric spectroscopy - Abstract
In this study, self-monitoring characteristics of a new piezoresistive structural polyester polymer composite bulk sensor were investigated under various loading conditions using impedance spectroscopy (IS). IS was used to estimate the bulk resistance of the piezoresistive polymer composite and the contact resistance of the two-probe measuring system used, along with the stress and shape dependence of these resistances. The piezoresistive behavior of cylindrical specimens in compression and circular disk specimens in bending and splitting tension showed repeatable characteristics. The contact resistances were about 1 % and 4.4 % of the bulk resistances for the cylindrical and circular disk specimens, respectively. The contact resistances were relatively small compared to the bulk resistances, and the change in contact resistance with applied stress was quantified. The average piezoresistivity coefficient for cylindrical specimens was 0.015 MPa−1 in compression, and for the circular disk specimens the coefficients were 3.1 × 10−4 MPa−1 and 4.62 × 10−4 MPa−1 under bending and splitting tensile loading, respectively. An incremental stress-resistivity model was used to predict the observed behavior of the piezoresistive polymer composite. more...
- Published
- 2013
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219. Flexural and Facture Properties of Glass Fiber Reinforced Polyester Polymer Concrete
- Author
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Cumaraswamy Vipulanandan and S. Mebarkia
- Subjects
Polyester ,Materials science ,Flexural strength ,Glass fiber ,Polymer concrete ,Composite material - Published
- 1996
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220. Performance of SteelPolymer Concrete Composite Structural Elements
- Author
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S. Wei, S. T. Mau, Cumaraswamy Vipulanandan, and S. K. Mantrala
- Subjects
symbols.namesake ,Materials science ,business.industry ,Composite number ,symbols ,Polymer concrete ,Young's modulus ,Structural engineering ,Composite material ,Ductility ,Compression (physics) ,business - Published
- 1996
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221. Nondestructive Evaluation of Polyester Polymer Concrete
- Author
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S. K. Mantrala and Cumaraswamy Vipulanandan
- Subjects
Damping ratio ,Materials science ,business.industry ,Modulus ,Young's modulus ,Polymer concrete ,Building and Construction ,Poisson's ratio ,symbols.namesake ,Nondestructive testing ,Dynamic modulus ,symbols ,General Materials Science ,Composite material ,business ,Elastic modulus ,Civil and Structural Engineering - Abstract
Nondestructive tests are gaining popularity for evaluating the properties of construction materials. In this study, the applicability of the impact resonance method and the ultrasonic pulse velocity method to polyester polymer and polymer concrete was investigated. The effect of specimen shape and size on the dynamic moduli, damping ratio, and pulse velocity were studied. The response of cylinders and prisms in the three fundamental modes of vibration, namely, longitudinal, transverse, and torsional, were investigated. From the longitudinal and transverse resonant frequencies, the dynamic Young's modulus of elasticity and damping ratio were determined. Using the torsional resonant frequency, the dynamic modulus of rigidity and dynamic Poisson's ratio were determined. Using the ultrasonic method, the pulse velocity in polymer and polymer concrete was measured at frequencies of 50 and 150 kHz. The dynamic modulus of elasticity was also determined from the pulse velocity and compared to the static modulus. The results of these nondestructive tests are reported. more...
- Published
- 1995
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222. Biosurfactant Production Using Mixed Cultures Under Non-Aseptic Conditions
- Author
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Cumaraswamy Vipulanandan, G. L. Ghurye, and Richard C. Willson
- Subjects
Surface tension ,Materials science ,Adsorption ,Biomass ,Yeast extract ,Centrifugation ,Food science ,Biodegradation ,Micelle ,Dilution - Abstract
Surfactants increase the accessibility of adsorbed hydrocarbons and mobilize immiscible petroleum hydrocarbons for treatment. Biosurfactants have the advantage of biodegradability and non-toxicity over their synthetic counterparts, and can be produced from renewable sources. In this study the production of biosurfactant from molasses was investigated in continuously stirred batch reactors. The effects of substrate concentration, yeast extract and peptone on biomass accumulation and biosurfactant production were investigated. Biosurfactant production was quantified by surface tension reduction and critical micelle dilution (CMD). Biosurfactant production was directly correlated with biomass production, and was improved with the addition of yeast extract. Centrifugation of the whole broth reduced surface tension. The performance of the biosurfactant produced from molasses under non-aseptic condition is comparable to other published results. more...
- Published
- 1994
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223. Stress-Strain Behavior and California Bearing Ratio of Artificially Cemented Sand
- Author
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Cumaraswamy Vipulanandan, Omer F. Usluogullari, R. E. Link, and M. R. Mitchell
- Subjects
Cement ,Curing time ,Compressive strength ,Materials science ,Mechanics of Materials ,Mechanical Engineering ,Stress–strain curve ,Unconfined compression ,Modulus ,General Materials Science ,Geotechnical engineering ,Composite material ,California bearing ratio - Abstract
In this study, effects of cement content and curing time on the compressive stress-strain relationship and California bearing ratio (CBR) value of artificially cemented sand cured up to 7 days was investigated. The CBR study was focused on investigating the sensitivity of this non-destructive test to measure the changes in the compacted cemented sand properties during construction (limited curing time). The cement content in the cemented sand was varied up to 6 % by weight. The strength, modulus, and unit weight of the artificially cemented sand varied from, 60 to 1250 kPa, 14 to 290 MPa, and 15.98 to 18.33 kN/m3, respectively. The CBR values for cemented sand, compacted using the standard proctor method, varied from 8 to 230 %. Compressive stress-strain relationship of cemented sand was represented by a non-linear relationship. Relationship between compressive properties of cemented sand and the CBR was also investigated. The variation of compressive strength, modulus, and CBR values with curing time were represented using hyperbolic relationships. Finite element method (FEM) was used to model the CBR test, based on the data obtained from the unconfined compression tests for 1.5, 3, and 6 % cemented sand. In the FEM analyses the cemented sand was modeled using linear elastic-perfectly plastic constitutive relationship with Mohr-Coulomb failure criteria. The ratio of predicted to measured CBR values varied from 0.67 to 1.31. more...
- Published
- 2011
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224. Factors Affecting Mechanical and Creep Properties of Silicate-Grouted Sands
- Author
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Jaroslav Feda, Alaa Ata, and Cumaraswamy Vipulanandan
- Subjects
Geotechnical Engineering and Engineering Geology ,General Environmental Science - Published
- 2000
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225. Fracture Toughness of Polymer Concrete
- Author
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Cumaraswamy Vipulanandan and N. Dharmandan
- Subjects
Materials science ,Fracture toughness ,Flexural strength ,visual_art ,visual_art.visual_art_medium ,Polymer concrete ,Epoxy ,Composite material - Published
- 1990
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226. Hot Wire Method to Characterize the Thermal Conductivity of Particle-Filled Polymer Grouts Used in Pipe-in-Pipe Application
- Author
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Sujan P. Kulkarni, Dmr Mitchell, and Cumaraswamy Vipulanandan
- Subjects
chemistry.chemical_classification ,Materials science ,Mechanical Engineering ,education ,Insulator (electricity) ,Polymer ,Microsphere ,Pipe in pipe ,Thermal conductivity ,chemistry ,Mechanics of Materials ,Heat transfer ,General Materials Science ,Composite material - Abstract
Insulated flowlines are considered a practical solution to prevent hydrate formation and paraffin deposition during the transportation of unprocessed well fluids to production facilities. A conventional pipe-in-pipe (PIP) system relies mainly on the heat transfer mode based on the thermal conductivity of the insulation material. Hence, in this study, a laboratory procedure was used to determine the thermal conductivity (k) of a polymer-based insulator (pumpable before setting) with and without filler materials. Microspheres ( more...
- Published
- 2006
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227. Leachability and biodegradation of high concentrations of phenol and O-chlorophenol
- Author
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Dennis A. Clifford, Deborah J. Roberts, and Cumaraswamy Vipulanandan
- Subjects
chemistry.chemical_compound ,Chemistry ,Phenol ,Biodegradation ,Waste Management and Disposal ,O-chlorophenol ,Nuclear chemistry - Published
- 1994
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228. Integrated process treatment train (bioremediation and immobilization) for texas soils contaminated with mixed hazardous waste
- Author
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Gerald E. Speitel, Cumaraswamy Vipulanandan, H. Mamidi, S. Wang, and G. L. Ghurye
- Subjects
Bioremediation ,Waste management ,Hazardous waste ,Process (engineering) ,Soil water ,Environmental engineering ,Environmental science ,Contamination ,Waste Management and Disposal - Published
- 1993
- Full Text
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229. In situ treatment for cracked and contaminated clays and permeable soils
- Author
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Cumaraswamy Vipulanandan, S. Wang, and M. Leung
- Subjects
In situ ,Environmental Engineering ,Health, Toxicology and Mutagenesis ,Soil water ,Environmental Chemistry ,Environmental science ,Geotechnical engineering ,Contamination ,Pollution ,Waste Management and Disposal - Published
- 1991
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230. Solidification/stabilization of organic waste using cementitious and polymeric materials
- Author
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S. Wang, Cumaraswamy Vipulanandan, and S. Krishan
- Subjects
Environmental Engineering ,Materials science ,Health, Toxicology and Mutagenesis ,Metallurgy ,Environmental Chemistry ,Solidification stabilization ,Biodegradable waste ,Cementitious ,Pollution ,Waste Management and Disposal - Published
- 1991
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231. Evaluation of Asymmetric Liposomal Nanoparticles for Encapsulation of Polynucleotides.
- Author
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Jeremiah Whittenton, Sivaram Harendra, Ramanan Pitchumani, Cumaraswamy Vipulanandan, Sundararajah Thevananther, and Kishore Mohanty
- Published
- 2008
- Full Text
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232. Characterization of Y2BaCuO5 nanoparticles synthesized by nano-emulsion method.
- Author
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Fang Li and Cumaraswamy Vipulanandan
- Subjects
- *
NANOPARTICLES , *TRANSMISSION electron microscopy , *LIGHT scattering , *SURFACE active agents - Abstract
Abstract Nanoscale yttrium–barium–copper oxide (Y2BaCuO5, Y211) particles were synthesized using the emulsion method and the solution method. The basic water-in-oil (w/o) emulsion system consisted of n-octane (continuous oil phase), cetyltrimethylammonium bromide (cationic surfactant), butanol (cosurfactant) and water. The composition of the emulsion system was varied and characterized by measuring the conductivity of the solutions and droplet size. The droplet size of emulsion was determined by using the dynamic light scattering method. The water content, cosurfactant content, and surfactant/n-octane ratio affected the droplet size which was in the range of 3–8 nm, and hence the w/o emulsion system was referred to as a nano-emulsion system. A model was used to verify the droplet size. The influence of salt (Y2(NO3)3) content on the droplet size was investigated and the addition of salt reduced the droplet size. The effects of reaction time and temperature on the Y211 particle sizes were also investigated. The particles were characterized using the TEM, SEM, and XRD. Nanoparticles produced by the nano-emulsion method were calcined at 850C to form the Y211 phase as compared to solid state processing temperature of 1050C. Based on the TEM analysis, the average diameter of the Y211 particles produced using the nano-emulsion method was in the range of 30–100 nm. The effect of adding 15% Y211 nanoparticles to the superconductor YBCO-123 as flux pinning centers, was investigated, and the transition temperature was reduced by 3 K. [ABSTRACT FROM AUTHOR] more...
- Published
- 2007
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233. Role of biosurfactants in enhancing the biodegradation of petroleum contaminated soils
- Author
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Richard C. Willson and Cumaraswamy Vipulanandan
- Subjects
chemistry.chemical_compound ,Contaminated soils ,Petroleum engineering ,chemistry ,Environmental chemistry ,Environmental science ,Petroleum ,Biodegradation ,Waste Management and Disposal - Published
- 1994
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234. Mechanical behaviour of polymer concrete systems
- Author
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N. Dharmarajan, Cumaraswamy Vipulanandan, and E Ching
- Subjects
chemistry.chemical_classification ,Materials science ,Flexural modulus ,Glass fiber ,General Engineering ,Modulus ,Stiffness ,Polymer concrete ,Building and Construction ,Epoxy ,Polymer ,Flexural strength ,chemistry ,Mechanics of Materials ,visual_art ,visual_art.visual_art_medium ,medicine ,General Materials Science ,medicine.symptom ,Composite material ,Civil and Structural Engineering - Abstract
The mechanical behaviour of epoxy and polyester polymer concrete systems was studied under different loading conditions at various temperatures, resin content, and glass fibre content. While polymer content varied between 10 and 20% of the total weight of polymer concrete, the fibre content was limited to 4% by weight. The temperature was varied between 22 and 110°C, depending on the glass transition temperature of the resin. Compared to vibration, the compaction method of preparation reduces the void content and enhances the strength and modulus of polymer concrete. The compressive and flexural strength and stiffness of the polymer concrete systems increase up to a certain limit of polymer content at which they exhibit maximum strength and stiffness. They subsequently decrease or remain almost constant with further increase in polymer content. The strength and stiffness of polymer concrete are very much dependent on the temperature. The stiffness model, based on inclusion theory, yields satisfactory results for the three-phase polymer concrete. Using this model, the compression and flexural modulus of polymer concrete can be predicted from the properties of the constituents and their composition. Incremental strength and stiffness models developed in this study are effective in predicting the increase in strength and stiffness of glass-fibre-reinforced polymer concrete. more...
- Published
- 1988
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235. Steady‐State Ice‐Structure Interaction Analysis
- Author
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Cumaraswamy Vipulanandan and A. N. Williams
- Subjects
geography ,geography.geographical_feature_category ,Steady state ,business.industry ,Mechanical Engineering ,Numerical analysis ,Mechanics ,Structural engineering ,Physics::Geophysics ,Seismic analysis ,Vibration ,Mechanics of Materials ,Boundary value problem ,Ice sheet ,business ,Physics::Atmospheric and Oceanic Physics ,Geology ,Plane stress ,Added mass - Abstract
Two-dimensional elastic wave theory is utilized to investigate the steady-state dynamic response of a cylindrical structure of elliptic cross section surrounded by an ice sheet of sinfinite extent. Fixed and frictionless boundary conditions at the ice-structure interface are considered under both plane stress and plane strain conditions. Numerical results are presented which show the effect of structural geometry, direction and frequency of vibration, and choice of boundary conditions on the dynamic characteristics of the ice-structure system. The analysis shows that the behavior of the ice-structure system is primarily controlled by the associated damping effects rather than the added mass. These results provide a measure of ice sheet resistance to the vibrational motion of structures surrounded by floating ice sheets and are applicable to the dynamic and seismic analysis of arctic offshore platforms. more...
- Published
- 1986
- Full Text
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236. Critical stress intensity factor of epoxy mortar
- Author
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N. Dharmarajan and Cumaraswamy Vipulanandan
- Subjects
Materials science ,Polymers and Plastics ,Flexural modulus ,Stiffness ,General Chemistry ,Bending ,Epoxy ,Fracture toughness ,Flexural strength ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,medicine ,Fracture (geology) ,Composite material ,Mortar ,medicine.symptom - Abstract
Fracture behavior of epoxy mortar was investigated in Mode I fracture using single edge notched beams with varying notch depth and beam thickness. The beams were loaded in both 3-point and 4-point bending. Influence of polymer content and temperature on the fracture behavior of epoxy mortar was studied using uniform Ottawa 20–30 sand. The polymer content was varied between 10 percent and 18 percent of the total weight of the composite. The temperature was varied between 22°C and 120°C. The flexural strength of the polymer mortar increases with increase in polymer content while the flexural modulus goes through a maximum. The critical stress intensity factor (KIC) was determined by several methods including compliance method (based on crack mouth opening displacement) and finite element analysis. The KIC for epoxy mortar increases with increase in polymer content and epoxy mortar strength but decreases with increase in temperature. The critical stress intensity factor of epoxy mortar is represented in terms of polymer content and polymer strength or stiffness. Numerical tests based on random sampling and stratified sampling procedures were performed to substantiate the experimentally observed fracture toughness values of epoxy mortar. more...
- Published
- 1988
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237. Critical crack tip opening displacement for polymer composites
- Author
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Cumaraswamy Vipulanandan and N. Dharmarajan
- Subjects
Materials science ,Mechanical Engineering ,Glass fiber ,Crack tip opening displacement ,Bending ,Epoxy ,Crack growth resistance curve ,Crack closure ,Mechanics of Materials ,visual_art ,Fracture (geology) ,visual_art.visual_art_medium ,General Materials Science ,Composite material ,Stress intensity factor - Abstract
Applicability of critical stress intensity factor ( K IC ) and/or critical crack up opening displacement (CTODc for epoxy and polyester polymer composites (PC) in mode I Fracture are investigated. Both unreinforced and glass fiber reinforced polymer composite systems are studied using single edge notched beams in three-point and four-point bending at room temperature. Crack mouth opening displacement method (CMOD) is used in determining the crack extension during pre-peak loading. The critical stress intensity factor is calculated at the tip of the effective crack and the critical crack extension is represented by the elastic crack tip opening displacement. A simple model has been developed to determine the elastic CTOD from the measured elastic CMOD, and the performance of this model is compared to several other models proposed for metals and cement concrete. The test results indicate that the two Fracture parameters are independent of initial notch depth. The two Fracture parameters are used in predicting the notch sensitivity of epoxy PC and polyester PC. Resistance curves based on stress intensity factor ( V R - curve ) and crack tip opening displacement ( V R - curve ) have been developed for the 4% glass fiber reinforced polyester PC. more...
- Published
- 1989
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238. Curing and constitutive relationships for polyester mortar
- Author
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Cumaraswamy Vipulanandan
- Subjects
Polyester ,Compressive strength ,Materials science ,Polymers and Plastics ,Ultimate tensile strength ,Constitutive equation ,Materials Chemistry ,Modulus ,General Chemistry ,Strain rate ,Composite material ,Mortar ,Curing (chemistry) - Abstract
The compressive and tensile properties of polyester mortar were studied under various curing conditions, temperature, and strain rate. The curing temperature was varied from room temperature to 80°C. The behavior of polyester mortar was studied using a uniform sand with strain rate and temperature varied between 0.01 to 6 percent strain per minute and 22°C and 120°C, respectively. The strength, failure strain, modulus and stress-strain relationships of polyester mortar are influenced by the curing method, testing temperature, and strain rate to varying degrees. The influence of test variables on the mechanical properties of polyester mortar are quantified. Pretreating the aggregates with a silane coupling agent further enhances the compressive and tensile strength of the mortar. The compressive modulus and splitting tensile strength of polyester mortar are related to the compressive strength. A constitutive model is used to predict the compressive stress-strain behavior of polyester mortar. more...
- Published
- 1989
- Full Text
- View/download PDF
239. Flexural behavior of polyester polymer concrete
- Author
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Cumaraswamy Vipulanandan and N. Dharmarajan
- Subjects
Polyester resin ,chemistry.chemical_classification ,Materials science ,Three point flexural test ,Flexural modulus ,Modulus ,Polymer concrete ,Building and Construction ,Flexural strength ,chemistry ,Ultimate tensile strength ,Void (composites) ,General Materials Science ,Composite material - Abstract
The effect of temperature, strain rate, resin content, void content and methods of preparation (vibration and compaction) on the overall flexural behavior of a polyester resin based polymer concrete is studied under three-point bending. The strength and modulus of polyester polymer concrete are relatively independent of strain rate but decrease at varying rates with increase in temperature. Compaction of polymer concrete during preparation reduces the void content and enhances both the flexural strength and modulus. Modifications to composite stiffness models have been proposed to include excess polymer and excess sand phases for systems other than the optimal system. Using a combination of parallel and series models, it is possible to predict the flexural modular ratio and flexural modulus of polymer concrete. Modified tensile strength models are effective in predicting the flexural strength ratio and flexural strength of polymer concrete. more...
- Published
- 1987
- Full Text
- View/download PDF
240. Mechanical Behavior of Chemically Grouted Sand
- Author
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Cumaraswamy Vipulanandan and Raymond J. Krizek
- Subjects
Materials science ,Bond strength ,Grout ,Failure strain ,Stiffness ,engineering.material ,Geotechnical Engineering and Engineering Geology ,Mixed mode ,Shear (geology) ,Ultimate tensile strength ,engineering ,medicine ,General Earth and Planetary Sciences ,Geotechnical engineering ,Adhesive ,medicine.symptom ,General Environmental Science - Abstract
Grouted sand is considered as a two-phase particulate composite in which both the cohesive and adhesive properties of the grout and the particle-to-particle interaction of the sand are considered to contribute toward the overall macro-response (strength, failure strain, stiffness, and failure modes) under tensile, shear, and compressive loadings. Adhesion tests were used to evaluate the interface bond under tensile, shear, and mixed mode loadings, and inclusion models were used to study failure mechanisms and how they affect the stress-strain relationship. The bond strength can be represented by a Mohr-Coulomb failure criterion, and the failure of grout and grouted sand can be approximated by a Drucker-Prager criterion. A theory has been proposed to explain the behavior of grouted sand, and tensile strength and stiffness models were developed to predict the properties of the grouted sand from the properties of the constituents. more...
- Published
- 1986
- Full Text
- View/download PDF
241. Effect of Interface Conditions on Dynamic Ice-Structure Interaction
- Author
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A. N. Williams and Cumaraswamy Vipulanandan
- Subjects
Stress (mechanics) ,Steady state ,Classical mechanics ,Interface (Java) ,Mechanical Engineering ,Shear stress ,Ocean Engineering ,Boundary value problem ,Mechanics ,Displacement (fluid) ,Geology - Abstract
Elastic wave theory is utilized to investigate the influence of interface boundary conditions on the dynamic characteristics of a circular cylindrical structure subjected to steady-state and impulsive horizontal excitation while surrounded by an elastic ice medium of infinite horizontal extent. The influence of modified interface boundary conditions relating the shear stresses to the relative displacement (slip) or relative velocity (rate of slip) on the stiffness and damping parameters are studied and the results are compared to the usual fixed and free boundary conditions on the cylinder surface. more...
- Published
- 1989
- Full Text
- View/download PDF
242. Performance of high temperature superconducting ceramic-polymer composite
- Author
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Cumaraswamy Vipulanandan, Krishnaswa Ravi-Chandar, and S. Salib
- Subjects
Superconductivity ,chemistry.chemical_classification ,Materials science ,Mechanical Engineering ,Sintering ,Young's modulus ,Polymer ,Condensed Matter Physics ,symbols.namesake ,chemistry ,Flexural strength ,Mechanics of Materials ,Meissner effect ,visual_art ,visual_art.visual_art_medium ,symbols ,General Materials Science ,Ceramic ,Composite material ,Electroceramics - Abstract
In order to improve the flexural properties of the high temperature superconducting ceramic (YBa 2 Cu 3 O 7− δ ) a thermoplastic polymer, poly(methylmethacrylate) (PMMA), is used. Ceramic specimens with different porosities were manufactured by dry compacting at various uniaxial pressures up to a maximum of 350 MPa. The organic polymer was impregnated into the porous ceramic at room temperature. The flexural properties were evaluated by concentrically loading simply supported disk specimens. Poly(methyl methacrylate) polymer increased the flexural strength and modulus of the superconducting ceramic without affecting its electrical properties. Property-porosity relationships have been developed for the superconducting ceramic with and without polymer. Polymer impregnation had no measurable effect on critical transition temperature, width of transition, and Meissner effect. more...
- Published
- 1989
- Full Text
- View/download PDF
243. Effect of temperature on the fracture properties of epoxy polymer concrete
- Author
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N. Dharmarajan and Cumaraswamy Vipulanandan
- Subjects
chemistry.chemical_classification ,Materials science ,Polymer concrete ,Building and Construction ,Epoxy ,Polymer ,Bending ,Edge (geometry) ,Critical value ,Surface energy ,chemistry ,visual_art ,visual_art.visual_art_medium ,Fracture (geology) ,General Materials Science ,Composite material - Abstract
Fracture behavior of epoxy polymer concrete was investigated at various temperature and resin content using single edge notched beams loaded in four-point bending. The temperature was varied between 22°C and 120°C and the polymer content between 10% and 18% of the total weight of polymer concrete. The results were analyzed to examine the applicability of various fracture parameters such as critical stress intensity factor (K IC ), critical value of J-integral (J IC ) and fracture surface energy γ IC to characterize the fracture behavior of epoxy polymer and polymer concrete. The K IC for both epoxy polymer and polymer concrete reduces with increase in temperature while J IC and γ IC go through a maximum within the range of temperature considered in this study. All the fracture parameters increase with increase in polymer content. Epoxy polymer is more notch sensitive than polymer concrete. While the notch sensitivity of epoxy polymer decreases with increase in temperature, 14% polymer concrete remains almost unchanged up to 60°C. more...
- Published
- 1988
- Full Text
- View/download PDF
244. Fracture Properties of Epoxy Polymer Concrete
- Author
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Cumaraswamy Vipulanandan and N. Dharmarajan
- Subjects
chemistry.chemical_classification ,Materials science ,Critical stress ,Polymer concrete ,Polymer ,Epoxy ,Surface energy ,Fracture toughness ,chemistry ,visual_art ,Fracture (geology) ,visual_art.visual_art_medium ,Composite material ,Intensity factor - Abstract
Epoxy polymer concrete beams with varying polymer content and notch depth were tested at two temperatures. The results were analysed to examine the applicability of various fracture parameters such as critical stress intensity factor, J-integral and fracture surface energy to characterize the fracture behavior of epoxy polymer and polymer concrete. The notch sensitivity of polymer and polymer concrete are also investigated. more...
- Published
- 1989
- Full Text
- View/download PDF
245. Processing and Performance of Metal Fiber Reinforced High Temperature Superconductor
- Author
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T. Stone, Cumaraswamy Vipulanandan, and S. Salib
- Subjects
High-temperature superconductivity ,Materials science ,Composite number ,Compaction ,Sintering ,Molding (process) ,law.invention ,law ,visual_art ,visual_art.visual_art_medium ,Ceramic ,Fiber ,Composite material ,Beam (structure) - Abstract
Aggregation of YBa2Cu3O7‐x powder by compaction molding and sintering results in porous ceramic with poor mechanical properties and hence improving the ceramic properties using continuous stainless steel fibers have been studied. Fiber reinforced beam specimens (2% of fibers by weight) were prepared by modifying the standard processing method. Fibers were pretreated with silver to reduce the contamination of the superconducting matrix. The mechanical and electrical properties of the superconducting ceramic‐fiber composite was evaluated at 77K. Continuous stainless steel fibers improved the performance of the superconducting ceramic. more...
- Published
- 1989
- Full Text
- View/download PDF
246. Analysis of Fracture Parameters of Epoxy-Polymer Concrete
- Author
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Cumaraswamy Vipulanandan and N. Dharmarajan
- Subjects
Materials science ,Flexural strength ,visual_art ,Fracture (geology) ,visual_art.visual_art_medium ,General Materials Science ,Polymer concrete ,Building and Construction ,Epoxy ,Composite material ,Civil and Structural Engineering - Published
- 1989
- Full Text
- View/download PDF
247. Behavior of Superconducting Ceramic-Polymer Composite
- Author
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Cumaraswamy Vipulanandan and S. Salib
- Subjects
Superconductivity ,chemistry.chemical_classification ,Materials science ,Composite number ,Electron microprobe ,Polymer ,Microanalysis ,chemistry.chemical_compound ,Flexural strength ,chemistry ,visual_art ,visual_art.visual_art_medium ,Ceramic ,Composite material ,Methyl methacrylate - Abstract
Poly (methyl methacrylate) (PMMA) was used to improve the flexural properties of the high temperature superconducting ceramics (YBa 2Cu3O7-x). The organic polymer was impregnated into the porous ceramic at room temperature. The flexural properties were evaluated using disk specimens. The interaction between the PMMA and ceramic was studied using electron probe microanalysis (EPMA). Poly (methyl methacrylate) polymer increased the flexural strength of the superconducting ceramic without affecting its electrical properties. Flexural strength relationships have been developed for the superconducting ceramic with and without polymer. Performance of the ceramic-polymer composite was also evaluated by thermocycling between 77k and 300k. more...
- Published
- 1989
- Full Text
- View/download PDF
248. Bonding Agent in Polyester Polymer Concrete
- Author
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Cumaraswamy Vipulanandan and N. Dharmarajan
- Subjects
Polyester ,chemistry.chemical_compound ,Materials science ,Flexural strength ,chemistry ,Glass fiber ,Polymer concrete ,Adhesion ,Composite material ,Silane - Published
- 1987
- Full Text
- View/download PDF
249. Field test for real time monitoring of piezoresistive smart cement to verify the cementing operations
- Author
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Hamid Farzam, Ahmed Mohammed, B. Basirat, Mourad Wagdy Ali, S. Dighe, A. Reddy, Cumaraswamy Vipulanandan, and Noha H. Amin
- Subjects
Cement ,Engineering ,Field (physics) ,business.industry ,Mechanical engineering ,02 engineering and technology ,010502 geochemistry & geophysics ,01 natural sciences ,Piezoresistive effect ,Civil engineering ,Test (assessment) ,020401 chemical engineering ,Instrumentation (computer programming) ,0204 chemical engineering ,business ,0105 earth and related environmental sciences - Abstract
In this study, a field well was installed and cemented using the smart cement mixture with enhanced piezoresistive properties. The field well was designed, built, and used to demonstrate the concept of real time monitoring of the flow of drilling mud and smart cement and hardening of the cement in place. The well was installed in soft swelling clay soils to investigate the sensitivity of the smart oil well cement. A new method has been developed to measure the electrical resistivity of the materials using the two probe method. Using the new concept, it has been proven that the resistivity dominated the behavior of drilling fluid and smart cement. LCR meters (measures the inductance (L), capacitance (C) and resistance (R)) were used at 300 kHz frequency to measure the changes in resistance. The well instrumentation was outside the casing with 120 probes, 18 strain gages and 9 thermocouples. The strain gages and thermocouples were used to compare the sensitivity of these instruments to the two probe resistance measure in-situ in the cement. The electric probes used to measure the resistance were placed vertically at 15 levels and each level had eight horizontal probes. Change in the resistance of hardening cement was continuously monitored since the installation of the field well for over 100 days. Also, a method to predict the changes in electrical resistance of the hardening cement outside the casing (Electrical Resistance Model - ERM) with time has been developed. The ERM predicted the changes in the electrical resistances of the hardening cement outside the cemented casing very well. In addition, the pressure testing showed the piezoresistive response of the hardened smart cement and a piezoresistive model has been developed to predict the pressure in the casing from the change in resistivity in the smart cement. more...
250. Polymer concrete in hazardous waste management: Applications
- Author
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O.I. Ghazzaly and Cumaraswamy Vipulanandan
- Subjects
Environmental Engineering ,Waste management ,Health, Toxicology and Mutagenesis ,Polymer concrete ,Thermal treatment ,Biodegradable waste ,Reuse ,Pollution ,Waste treatment ,Hazardous waste ,Environmental Chemistry ,Environmental science ,Leachate ,Inert waste ,Waste Management and Disposal - Abstract
There is no universal waste treatment or immobilization process that will handle all the variation of waste produced, which is estimated to be between 27 to 60 million tons per year nation wide and 7 million in the gulf coast region. The key preventive measures for minimizing the hazardous waste problem are waste control, reduction, reuse, stabilization, solidification and encapsulation. In this regard developing and/or modifying additives for solidification and materials for encapsulation to meet the current demands in hazardous waste disposal has drawn tremendous interest. Polymer concrete (PC) with its rapid-setting, high-strength, low permeability and high corrosive resistance appears to be a potential material for use in hazardous waste management and recent applications have shown promising results. PC is a composite material formed by combining mineral aggregates such as sand and gravel with a polymerizing monomer. Compared to polymers, PC systems will be cost effective, since only 20 to 25% (by volume) of polymer is used in the PC composite. The objectives of this study are to select and characterize PC systems in solidification and encapsulation processes by bench-scale process development. Several polymers will be selected but special consideration will be given to polybutadiene, polyvinyl chloride and polyester. Optimum PC systems based on low permeability, high mechanical strength and high corrosive resistance will be developed. Two hazardous waste materials will be selected for the preliminary study with one inorganic waste and the other organic waste that are not easily treatable by other methods. The selected PC systems will be used for solidification and/or encapsulation of the inorganic and organic wastes. The treated waste will be investigated for leachate and mechanical properties. more...
- Published
- 1989
- Full Text
- View/download PDF
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