A Proposed Interscholastic Track and Field Training Program for the Junior High School

The purpose of this study is to develop an interscholastic track and field training program suitable to the junior high school level student

Analysis of Temperatures at a Municipal Solid Waste Landfill

A study is conducted to determine the thermal regime within and around a municipal solid waste landfill located in midwestern U.S.A. Spatial distributions of temperatures have been determined over time since 1999 within the waste mass, liner and cover systems, and surrounding subgrade. Seasonal variations, placement of waste, age of waste, depth and location of waste, and available moisture have significant effects on temperatures. Temperatures of wastes at shallow depths, bottom liner systems prior to waste placement, and final cover systems conform to seasonal temperature variations. Steady elevated temperatures are reached with respect to air and ground temperatures at central locations and at depth in the waste mass. Increasing trends are observed for temperatures in wastes and bottom liner systems in cells containing newly placed wastes. It is estimated that waste temperatures increased due to effects of leachate recirculation at portions of the facility. Subgrade temperatures at the perimeter of the landfill have not yet been significantly affected by the presence of the facility

Temperature effects on the swelling and bentonite extrusion characteristics of GCLs

This investigation was conducted to evaluate effects of temperature on swelling and bentonite extrusion properties of GCLs. The swelling characteristics were determined using standardized test procedures and extrusion characteristics were determined using a new test method developed by the authors. Tests were conducted on a conventional medium-weight woven/nonwoven GCL. The range of test temperatures was 2 to 98°C (swelling tests) and -5 to 100°C (extrusion tests). The extrusion tests were conducted under stresses between 100 and 400 kPa and moisture contents between 50 and 150%. Temperature had significant effects on both swell and extrusion. The swell index ranged from 21 mL/2g at 2°C to 36.5 mL/2g at 98°C, with the largest increase occurring from 20 to 40°C. The amount of extrusion ranged from nearly 0 to 40.5 g/m2 with generally decreasing extrusion with temperature from 2 to 100°C. At a given temperature, extrusion increased with increasing stress and moisture content

Implications of variable waste placement conditions for MSW landfills

This investigation was conducted to evaluate the influence of waste placement practices on the engineering response of municipal solid waste (MSW) landfills. Waste placement conditions were varied by moisture addition to the wastes at the time of disposal. Tests were conducted at a California landfill in test plots (residential component of incoming wastes) and full-scale active face (all incoming wastes including residential, commercial, and self-delivered components). The short-term effects of moisture addition were assessed by investigating compaction characteristics and moisture distribution and the long-term effects by estimating settlement characteristics of the variably placed wastes. In addition, effects on engineering properties including hydraulic conductivity and shear strength, as well as economic aspects were investigated. The unit weight of the wastes increased with moisture addition to a maximum value and then decreased with further moisture addition. At the optimum moisture conditions, 68% more waste could be placed in the same landfill volume compared to the baseline conditions. Moisture addition raised the volumetric moisture content of the wastes to the range 33–42%, consistent with values at and above field capacity. Moisture transfer occurred between consecutive layers of compacted wastes and a moisture addition schedule of 2 days of as-received conditions and 1 day of moisture addition was recommended. Settlement of wastes was estimated to increase with moisture addition, with a 34% increase at optimum moisture compared to as-received conditions. Overall, moisture addition during compaction increased unit weight, the amount of incoming wastes disposed in a given landfill volume, biological activity potential, and predicted settlement. The combined effects have significant environmental and economic implications for landfill operations

Waste heat generation: A comprehensive review

A comprehensive review of heat generation in various types of wastes and of the thermal regime of waste containment facilities is provided in this paper. Municipal solid waste (MSW), MSW incineration ash, and mining wastes were included in the analysis. Spatial and temporal variations of waste temperatures, thermal gradients, thermal properties of wastes, average temperature differentials, and heat generation values are provided. Heat generation was influenced by climatic conditions, mean annual earth temperatures, waste temperatures at the time of placement, cover conditions, and inherent heat generation potential of the specific wastes. Time to onset of heat generation varied between months and years, whereas timelines for overall duration of heat generation varied between years and decades. For MSW, measured waste temperatures were as high as 60–90 °C and as low as −6 °C. MSW incinerator ash temperatures varied between 5 and 87 °C. Mining waste temperatures were in the range of −25 to 65 °C. In the wastes analyzed, upward heat flow toward the surface was more prominent than downward heat flow toward the subsurface. Thermal gradients generally were higher for MSW and incinerator ash and lower for mining waste. Based on thermal properties, MSW had insulative qualities (low thermal conductivity), while mining wastes typically were relatively conductive (high thermal conductivity) with ash having intermediate qualities. Heat generation values ranged from −8.6 to 83.1 MJ/m3 and from 0.6 to 72.6 MJ/m3 for MSW and mining waste, respectively and was 72.6 MJ/m3 for ash waste. Conductive thermal losses were determined to range from 13 to 1111 MJ/m3 yr. The data and analysis provided in this review paper can be used in the investigation of heat generation and thermal regime of a wide range of wastes and waste containment facilities located in different climatic regions

Analytical and Numerical Methodology for Modeling Temperatures in Landfills

Analytical and numerical approaches have been developed for modeling temperatures in municipal solid waste landfills. Steps for model formulation and details of boundary conditions are described. The formulation was based on a transient conductive heat transfer analysis. Conventional earth temperature theories were modified for landfill systems by incorporating heat generation functions representing biological decomposition of wastes. Finite element analysis was used for general modeling and parametric evaluations. Thermal properties of materials were determined using field observations and data reported in literature. The boundary conditions consisted of seasonal temperature cycles at the ground surface (established using near-surface field measurements) and constant temperatures at the far-field boundary (established using field measurements and maps of regional groundwater temperatures). For heat generation, first a step-function was developed to provide initial (aerobic) and residual (anaerobic) conditions. Second, an exponential growth-decay function was established; and third, the function was scaled for climatic conditions. The formulations developed can be used for prediction of temperatures within various components of landfill systems (liner, waste mass, cover, and surrounding subgrade), determination of frost depths, and determination of heat gain due to decomposition of wastes

Use of Post-Consumer Corrugated Fiberboard as Fine Aggregate Replacement in Controlled Low-Strength Materials

This study was conducted to investigate the use of post-con­sumer corrugated board in controlled low-strength material (CLSM) applica­tions. Corrugated fiberboard (termed corrugate), which constitutes a significant fraction of the municipal solid waste stream in the United States (approximately one third by weight), was used as a partial replacement for fine aggregate in CLSM at aggregate replacement ratios ranging from 0 % (i.e., control) to 6 %. The corrugate was fiberized (i.e., repulped) in a blender prior to being mixed with other constituents in the CLSM. The density, air con­tent, and flow consistency of the fresh CLSM were determined, and bleeding was qualitatively assessed. Also, the unconfined compressive strength was determined for the resulting mixtures at different test ages. As the corrugate content increased, air content and water demand increased, density and compressive strength decreased, and some mixtures exhibited excessive bleeding. Corrugated fiberboard was determined to be effective as a fine ag­gregate replacement to produce mixtures with 28-day compressive strengths within the range for excavatable CLSM

Changing the Light Bulb in Higher Education: Transforming Internationalization

In this chapter, Dr. Jim Barber (associate professor, School of Education), Dr. Pam Eddy (professor, School of Education), and Dr. Steve Hanson (vice provost for International Affairs and director, Reves Center for International Studies) explore how the transformation on internationalization at the College of William & Mary. I was pleased to hear their thoughts about the personal and professional benefits of reflecting on their institutional impact.https://scholarworks.wm.edu/educationbookchapters/1009/thumbnail.jp

Footrot of cattle

1 online resource (PDF, 2 pages)This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu