Civil and Environmental Engineering Commons^™

Pc Windows Finite Element Modeling Of Landfill Gas Flow, Stephen R. Mull, Robert L. Lang, Samuel A. Vigil, Harold M. Cota

Civil and Environmental Engineering

A two dimensional demonstration program, GAS, has been developed for the solution of landfill gas (LFG) flow problems on a personal computer (PC). The program combines a Windows™ graphical user interface, object oriented programming (OOP) techniques, and finite element modeling (FEM) to demonstrate the practicality of performing LFG flow modeling on the PC. GAS is demonstrated on a sample LFG problem consisting of a landfill, one gas extraction well, the landfill liner, cap, and surrounding soil. Analyses of the program results are performed for successively finer grid resolutions. Element flux imbalance, execution time, and required memory are characterized as a …

Testing Of Concrete Under Closed-Loop Control, Ravindra Gettu, Barzin Mobasher, Sergio Carmona, Daniel C. Jansen

Civil and Environmental Engineering

Closed-loop testing systems provide the ability to directly control the deformation of the loaded specimen. This considerably enhances the precision, stability, and scope of the experiments. Closed-loop machines can be used to determine the stable response of test specimen or structure by monitoring and controlling the physical quantities that are sensitive to its behavior. The importance of the various components of the closed-loop controlled system and the test configuration is reviewed in the paper. The most critical aspect of designing the test is the choice of the controlled variable. With appropriate controlled variables and good system performance, several interesting and …

Comparison Of Load Restriction Timings Determined Using Fhwa Guidelines And Frost Tubes, Nazli Yesiller, Craig H. Benson, Peter J. Bosscher

Civil and Environmental Engineering

The Federal Highway Administration (FHwA) method and frost-tube measurements are used in Wisconsin to determine the timing and duration of spring load restrictions. In both methods, depth of freeze or thaw is used to determine when to apply load restrictions and to determine their duration. Average daily air temperatures are used in the FHwA method to predict the start and end of freeze and/or thaw. Frost tubes are used to directly determine depth of freeze and/or thaw. An analysis is conducted to compare these two methods using air-temperature data (for the FHwA method) and frost-tube data obtained in Wisconsin. The …

Hazardous Waste Management, Harold M. Cota, David Wallenstein

Civil and Environmental Engineering

Hazardous waste management is a broad and evolving field. Applicable state and federal regulations comprising over 60,000 pages are continually being updated. Many of these regulations overlap and are subject to differences in interpretation that often lead to court rulings. Regulations, economic pressures and public perception are forcing companies to rapidly change the way they manufacture products in order to minimize hazardous waste generation. Over 200 million tons of solid hazardous waste are generated annually in the United States. Huge quantities of hazardous waste deposited in landfills, ponds, fields, and other locations require removal or in situ treatment. Common hazardous …

Ultrasonic Nondestructive Testing Method For Evaluation Of Annular Seals, Nazli Yesiller

Civil and Environmental Engineering

No abstract provided.

Lead Distribution In A Simulated Aquatic Environment: Effects Of Bacterial Biofilms And Iron Oxide, Yarrow M. Nelson, Waihung Lo, Leonard W. Lion, Michael L. Shuler, William C. Ghiorse

Civil and Environmental Engineering

Biofilms influence the transport and fate of heavy metals in aquatic environments both directly by adsorption and complexation reactions and indirectly via interactions with oxides of iron and manganese. These reactions were investigated by introducing lead into a continuous-flow biofilm reactor that was designed to simulate conditions in a flowing freshwater aquatic environment. The reactor provided controlled conditions, and use of a chemically-defined growth medium allowed calculation of lead speciation with a chemical equilibrium program (MINEQL). Pseudomonas cepacia was employed as a test cell strain because of its ability to grow and form biofilms in the defined medium. This bacterium …

Development Of A Graduate Integrated Waste Management Course Using The Case Study Approach, Samuel A. Vigil

Civil and Environmental Engineering

Solid waste management is an integral part of the environmental engineering profession. At California Polytechnic State University (Cal Poly), solid waste management is taught as a required course in an undergraduate environmental engineering curriculum. The undergraduate course is described in Reference 1. This paper discusses the development of a graduate level integrated waste management course entitled "Resource and Energy Recovery from Waste", which uses a case study approach. The course focuses on resource and energy recovery technologies including composting, unit operations of resource recovery, recycling, and thermal waste conversion including combustion and gasification. The bioconversion of wastes in landfills and …

Application Of Macro Material Flow Modeling To The Decision Making Process For Integrated Waste Management Systems, Samuel A. Vigil, Gregory M. Holter

Civil and Environmental Engineering

Computer models have been used for almost a decade to model and analyze various aspects of solid waste management. Commercially available models exist for estimating the capital and operating costs of landfills, waste-to-energy facilities and compost systems and for optimizing system performance along a single dimension (e.g. cost or transportation distance).

An alternative to the use of currently available models is the more flexible macro material flow modeling approach in which a macro scale or regional level approach is taken. Waste materials are tracked through the complete integrated waste management cycle from generation through recycling and reuse, and finally to …

Closure To "Seismic Code Analysis Of Buildings Without Locating Centers Of Rigidity", Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

No abstract provided.

Comparison Of The Environmental Effects Of Aerobic And Anaerobic Composting Technologies, Samuel A. Vigil, George Tchobanoglous

Civil and Environmental Engineering

The biological conversion of yard wastes and municipal solid waste by aerobic composting is an established technology. Anaerobic conversion of these wastes is less practiced but is being widely advocated for the next generation of bioconversion systems. Although the operational characteristics of both types of systems is well known, there is a lack of quantifiable data in the literature on the environmental effects of these technologies. It is widely assumed that they are environmentally benign, especially as compared to other processing and conversion technologies such as incineration or mechanical processing. The process microbiology, design, and operational characteristics of aerobic and …

Seismic Response Study Of The Us 101/Painter Street Overpass Using Strong Motion Records, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

Abutment stiffnesses are determined directly from the earthquake motions recorded at the US 101/Painter Street Overpass using a simple equilibrium-based approach without finite-element modeling of the structure or the abutment-soil systems. The calculated abutment stiffnesses, which include the effects of soil-structure interaction and nonlinear behavior of the soil, are used to investigate variation of the abutment stiffness with its deformation during the earthquake and torsional motions of the road deck. Also evaluated are the CALTRANS, ASSHTO-83, and ATC- 6 procedures for estimating the abutment stiffness. It is demonstrated that stiffness of the abutment depends significantly on its deformation during the …

Dual-Level Approach For Seismic Design Of Asymmetric-Plan Buildings, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

Buildings should be designed to resist moderate ground motion without structural damage and resist intense ground motion with controlled damage. However, most codes do not consider both these requirements explicitly and specify a single design earthquake that generally corresponds to intense ground motion. Investigated in this study is the response of one-story, asymmetric-plan systems designed according to torsional provisions of seismic codes to the two levels of ground motions with the objective of evaluating whether such systems satisfy these requirements. The presented results demonstrate that such systems may not remain elastic during moderate ground motion resulting in structural damage and …

Seismic Code Analysis Of Buildings Without Locating Centers Of Rigidity, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

Static force procedures of most building codes require that the lateral earthquake force at each floor level of an asymmetric-plan building be applied eccentrically from the centers of rigidity. To implement such procedures, it seemed necessary in the past to determine the locations of the centers of rigidity, an often confusing and cumbersome process. This paper presents a new approach for code lateral force analysis of asymmetric-plan buildings without locating the centers of rigidity. This procedure combines the results from three static analyses, which can be implemented directly on most commercially available computer programs for analysis of multistory buidings. The …

Vinyl Chloride Biodegradation With Methanotrophic Attached Films, Yarrow M. Nelson, William J. Jewell

Civil and Environmental Engineering

Methanotrophic degradation of vinyl chloride (VC) is investigated using a laboratory-scale methanotrophic attached-film expanded-bed (MAFEB) bioreactor. This study provides a basis for applying a microbial cometabolizing reaction to practical treatment of toxic chlorinated compounds. The MAFEB reactor was operated at 20°C with influent VC concentrations ranging from 1,800 to 9,600 µg/L and bed hydraulic retention times ranging from 3.7 to 7.6 h. VC effluent concentrations during steady continuous operation ranged from 3 to 140 µg/L, with most values less than 26 µg/L, resulting in removal efficiencies of 96.3% to 99.8%. The maximum continuous-flow VC degradation rate observed at 20°C was …

The Naval Reserve Civil Engineer Corps Environmental Engineering Program, William A. Heine, Samuel A. Vigil

Civil and Environmental Engineering

The Navy is engaged in a national effort to bring its shore facilities into compliance with all applicable local, state, and federal environmental regulations. This work is being completed by civil service employees, consultants, and contractors under the supervision of Navy Civil Engineer Corps officers. To supplement these active duty and civilian resources, the Reserve Division of the Naval Facilities Engineering Command (RDNAVFAC) has identified Reserve officers with substantial environmental engineering skills who are being assigned to assist Navy shore activities all over the world in this essential task. The Naval Reserve Civil Engineer Corps (CEC) is composed of over …

Evaluation Of Us Seismic Code Provisions For Asymmetric-Plan Systems, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

The effects of plan asymmetry on the earthquake response of code-designed, one-story systems are identified with the objective of evaluating how well these effects are represented by torsional provisions in US building codes. The earthquake-induced deformations and ductility demands on resisting elements of asymmetric-plan systems, are compared with their values if the system plan were symmetric. The presented results demonstrate that the design eccentricity in US building codes should be modified in order to achieve the desirable goal of similar ductility demands on asymmetric-plan and symmetric-plan systems. The design eccentricity should be defined differently depending on the design value of …

Methanotrophic Bacteria For Nutrient Removal From Wastewater: Attached Film System, William J. Jewell, Yarrow M. Nelson, Mark S. Wilson

Civil and Environmental Engineering

It was hypothesized that nutrient removal from wastewater could be achieved by using methane oxidizing bacteria (methanotrophs). Because methane is inexpensive. it can be used as an energy source to encourage bacterial growth to assimilate nitrogen and phosphorus and other trace elements. This initial feasibility study used synthetic nutrient mixtures and secondary sewage effluent as feed to a laboratory-scale methanotrophic attached-film expanded bed (MAFEB) reactor operated at 35°C and 20°C. The MAFEB system operated successfully at low nutrient concentrations under a variety of nutrient-limited conditions. Using a synthetic nutrient mixture with a nitrogen:phosphorus feed ratio (w/w) …

Graphical Integrated Waste Management Model For Puerto Rico, Samuel A. Vigil, Hilary M. Theisen

Civil and Environmental Engineering

The application of STELLA, a commercially available, graphically based simulation language for the Macintosh computer, to solid waste facility planning is described. This paper discusses a STELLA model which was developed for the Commonwealth of Puerto Rico Solid Waste Management Authority (SWMA). The model simulates the existing solid waste management system in Puerto Rico and also the proposed system of regional landfills, transfer stations, and waste-to-energy plants. The model incorporates population projections for all 78 municipalities in Puerto Rico from 1990 to 2010, solid waste generation factors for all municipalities, data on remaining life for the existing landfills, and projected …

Development Of Solid Waste Management Courses At The Undergraduate And Graduate Level, Samuel A. Vigil, George Tchobanoglous

Civil and Environmental Engineering

Management of solid wastes in a cost effective and environmentally sensitive manner has become one of the most challenging infrastructure issues facing municipalities today. The problem is exacerbated by a shortage of qualified engineers. In this paper, both undergraduate and graduate courses in solid waste management that have been taught by the authors at their respective universities for over 20 years are described and available textbooks and reference materials are discussed.

Evaluation Of Torsional Provisions In Seismic Codes, Anil K. Chopra, Rakesh K. Goel

Civil and Environmental Engineering

The effects of plan asymmetry on the earthquake response of code-designed, one-story systems are identified with the objective of evaluating how well these effects are represented by torsional provisions in building codes. The earthquake-induced deformations and ductility demands on resisting elements of asymmetric-plan systems, designed according to several different codes, are compared with their values if the system plan were symmetric. The presented results demonstrate that the design eccentricity in building codes should be modified in order to achieve the desirable goal of similar ductility demands on asymmetric-plan and symmetric-plan systems. The design eccentricity should be defined differently for elastic …

Effects Of Plan Asymmetry In Inelastic Seismic Response Of One-Story Systems, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

The effects of plan asymmetry on the earthquake response of one-story systems are identified by comparing the dynamic response of an asymmetric-plan system and the corresponding symmetric-plan system for a wide range of system parameters—uncoupled lateral vibration period, uncoupled torsional-to-lateral frequency ratio, stiffness eccentricity, and yield factor. Elastic as well as inelastic systems are studied. For the latter, two values of the strength eccentricity are considered: equal to the stiffness eccentricity and zero; the latter is representative of code-designed buildings. Based on the response results for a wide range of system parameters, this paper identifies how the structural response is …

Low Cost Software, Harold M. Cota

Civil and Environmental Engineering

This is the fifth in our series on low cost software available to JAPCA readers. These programs have been developed by APCA members and are provided as a professional courtesy, as is, without warrantee. The authors would appreciate any feedback you have. In addition, we hope you will be willing to share programs you have developed for your own PC. To share your program all you need to do is prepare a brief description, similar to those in this column and send it with your program and any examples or documentations you are willing to furnish to: Dr. Hal Cota, …

Surabaya Indonesia: Options In Solid Waste Management, Samuel A. Vigil

Civil and Environmental Engineering

The Government of Indonesia requested assistance from the United States Trade and Development Program (TDP) regarding improvements to the solid waste management system of the City of Surabaya. TDP retained the author to prepare a Preliminary Feasibility Study which will enable TDP to make an informed decision on the desirability of funding further engineering work leading to solid waste projects.

Microcomputer Model For Solid Waste Planning, Samuel A. Vigil, Jane A. Zevely, Roy Yeaman

Civil and Environmental Engineering

No abstract provided.

Source Testing Software, Harold M. Cota

Civil and Environmental Engineering

Ifyou have been looking for a way to speed the calculation or reporting of source test data, this month's column will be of interest to you. Included in this review are one commercial program, several noncommercial programs, and a summary of programs that are available for programmable calculators. The author would appreciate knowing of similar programs that you may have developed or used.

Microcomputer Solid Waste Financial Model, Samuel A. Vigil, Jane A. Zevely

Civil and Environmental Engineering

Applications of a microcomputer based solid waste financial model will be described. The model is written as an overlay to the Lotus 1-2-3 spreadsheet program. It makes use of the Lotus 1-2-3 macro programming capabilities and is menu driven, requiring minimal computer skills for use. The model allows engineers to estimate costs for recycling centers, waste-to-energy plants, and landfills. Outputs include summary tables of operational and capital costs, as well as a 20 year proforma income statement. The model was developed for the California Waste Management Board, an agency of the State of California, and will be distributed by them.

Method And Apparatus For Generating Electrical Energy From A Heated Gas Containing Carbon Particles, Samuel A. Vigil, Rick B. Spielman

Civil and Environmental Engineering

Carbon particles entrained in the gas flow into a magnetohydrodynamic generator are electrostatically charged from a source of high voltage and then function as charge carriers in the MHD process. Lower flow temperatures may be used and seeding with alkali metal salts is unnecessary as the MHD process becomes independent of thermal ionization of constituents of the gas flow.

Solid Waste Resource Recovery Alternatives, U.S. Facility, Subic Bay, Philippines, Samuel A. Vigil, R. M. Roberts, Donald E. Brunner

Civil and Environmental Engineering

The U.S. Navy Public Works Center, Subic Bay, Republic of the Philippines (PWC Subic Bay) is responsible for the collection and disposal of almost 300,000 yd³ of solid waste annually. A portion of this solid waste is manually sorted and recycled, resulting in gross revenues of over $200,000 in FY82. The present manual sorting and recycling system is considered by PWC Subic Bay to be inadequate in terms of sanitation, safety, and recyclable materials recovery. Therefore , PWC Subic Bay requested that the Naval Civil Engineering Laboratory (NCEL) study the system and recommend improvements.

Low Technology Recycling And Rdf System At The U.S. Facility, Subic Bay, Philippines, Samuel A. Vigil, Donald E. Brunner

Civil and Environmental Engineering

The U.S. Facility Subic Bay is located about 50 miles east of Manila, on the East China Sea. The Facility consists of seven major Naval installations. The Facility is essentially a large commercial/industrial complex. The Public Works Center (PWC) Subic Bay is the public works agency responsible for the collection and disposal of the solid waste produced by the facility. A portion of the solid waste is manually sorted and recycled. Although the present manual sorting and recycling system is effective, PWC Subic Bay feels that it can be improved. Therefore , the Naval Civil Engineering Laboratory (NCEL) was requested …

Performance And Economic Feasibility Of A Sludge/Wastepaper Gasifier System, N. W. Sorbo, George Tchobanoglous, John R. Goss, Samuel A. Vigil

Civil and Environmental Engineering

Thermal gasification of densified sludge/wastepaper fuels has been shown to be technically feasible for the co-disposal of sludge and source-separated wastepaper. The performance and economic feasibility of a downdraft packed-bed gasifier system fueled with densified sludge/wastepaper and wastepaper fuels has been evaluated.

To assess the performance of the gasifier, a series of gasifier runs were conducted at various air input rates with the use of various densified fuels. In eight of the runs, a densified fuel consisting of 20 percent lagoon-dried sludge and 80 percent recycled wastepaper was used; in five runs, densified wastepaper cubes were used. Gaseous and particulate …