Emission Control in Coking Operations By Use of Stage Charging

At the Clairton Coke Works of the United States Steel Corporation (the world’s largest coke plant), with coal charges of about 30,000 net tons per day, a system designated as “stage charging” has been developed for charging coal into the coke oven chamber without emissions to the atmosphere. The principles of the system are based on controlled sequential flow of the coal from the charging hoppers, during which the oven chamber is maintained under a very slight negative pressure condition by use of steam aspiration in the offtakes for on-the-main charging. The techniques are basic but require knowledge of the coal characteristics, adequate and properly maintained aspirating systems, including clean offtake piping, control of coal volume in the individual hoppers, and last, and probably most important, adherence by the operating crew to specific charging and leveling practices.     

Biodiversity and Conservation of Plants in Brazil

Abstract:  With more than 56,000 species (excluding fungi), Brazil has one of the richest floras in the world—nearly 19% of the world flora. Our knowledge of the diversity and status of nonvascular plants in Brazil is still fragmentary, although localized studies on algae have revealed loss of species resulting from environmental pollution. Emphasis on local floral surveys, rather than wider taxonomic studies, has obscured estimates of national totals for most taxonomic groups. Knowledge of angiosperms, especially monocotyledons (of which 45% of the species are endemic), is more complete than most. For this group figures are more reliable, with some distribution patterns, endemism levels, and centers of diversity identified. Much, however, still awaits discovery. Coordinated efforts to catalog Brazil's flora are in progress and include projects such as the conservation priority-setting workshops of the Brazilian Ministry of the Environment, which have identified key conservation areas in the major biomes; development of threatened species lists for plants; and the assembly of type data on species of northeastern Brazil through the Darwin Initiative—all of which greatly assist in increasing our knowledge. These initiatives also underline the urgent need to expand the numbers and geographic spread of projects on plant systematics and taxonomy in Brazil, a measure that demands adequate provision of funding and training programs for plant specialists. Finally, Brazil's environmental agency (IBAMA) could play a proactive role in opening protected areas under its jurisdiction, thereby facilitating botanical research by university departments and research institutes.     

ASSAULT PREVENTION AS SOCIAL CONTROL: WOMEN AND SEXUAL ASSAULT PREVENTION ON URBAN COLLEGE CAMPUSES

Sexual assault on U.S.A. college campuses is increasingly recognized as an urgent and pervasive national problem. To prevent assault, school administrators and individual women promote and adopt safety strategies that often compromise women's free and independent use of the campus environment. Such strategies may fail to correspond to the actual nature of sexual assault on campus. Based on open-ended interviews with college personnel and women students, this study examines sexual assault and personal crime prevention strategies at two midwestern, urban universities. School and individual strategies are characterized according to type, goals, and orientation. Findings explore the relationship of strategies to sexual assault on campus, and implications of strategies for women's use of public space. Conclusions suggest means to increase real safety while enhancing women's freedom and mobility on and near campus.     

Climate Sensitivity of Phosphorus Loadings to an Urban Stream

We investigate the sensitivity of phosphorus loading (mass/time) in an urban stream to variations in climate using nondimensional sensitivity, known as elasticity, methods commonly used by economists and hydrologists. Previous analyses have used bivariate elasticity methods to represent the general relationship between nutrient loading and a variable of interest, but such bivariate relations cannot reflect the complex multivariate nonlinear relationships inherent among nutrients, precipitation, temperature, and streamflow. Using fixed‐effect multivariate regression methods, we obtain two phosphorus models (nonparametric and parametric) for an urban stream with high explanatory power that can both estimate phosphorus loads and the elasticity of phosphorus loading to changes in precipitation, temperature, and streamflow. A case study demonstrates total phosphorus loading depends significantly on season, rainfall, combined sewer overflow events, and flow rate, yet the elasticity of total phosphorus to all these factors remains relatively constant throughout the year. The elasticity estimates reported here can be used to examine how nutrient loads may change under future climate conditions.     

Sleep and the sleep environment temperature

EEG's and skin temperature measurements were made on six men and six women while sleeping in environments whose temperatures were 10·0°C, 21·1°C, and 32·2°C. Analysis of the EEG recordings showed that the proportion of time in each sleep stage was not affected by the temperature of the sleep environment. The weighted mean skin temperatures of the subjects were similar for the 10·0°C and 21·1°C condition, with a mean of 34·5°C for the sleep period. The mean weighted skin temperature for the 32·2°C condition was 35·6°C. A questionnaire administered when the subjects had awakened showed that women did not sleep as well at 10·0°C as at the other temperatures, when sleeping in conventional bedding and clothing.     

Risk assessment in the face of a changing environment: gypsy moth and climate change in Utah.

The importance of efficaciously assessing the risk for introduction and establishment of pest species is an increasingly important ecological and economic issue. Evaluation of climate is fundamental to determining the potential success of an introduced or invasive insect pest. However, evaluating climatic suitability poses substantial difficulties; climate can be measured and assessed in a bewildering array of ways. Some physiological filter, in essence a lens that focuses climate through the requirements and constraints of a potential pest introduction, is required. Difficulties in assessing climate suitability are further exacerbated by the effects of climate change. Gypsy moth (Lymantria dispar L.) is an exotic, tree-defoliating insect that is frequently introduced into the western United States. In spite of an abundance of potential host species, these introductions have yet to result in established populations. The success of eradication efforts and the unsuccessful establishment of many detected and undetected introductions may be related to an inhospitable climate. Climatic suitability for gypsy moth in the western United States, however, is potentially improving, perhaps rapidly, due to a general warming trend that began in the mid 1970s and continues today. In this work, we describe the application of a physiologically based climate suitability model for evaluating risk of gypsy moth establishment on a landscape level. Development of this risk assessment system first required amassing databases that integrated the gypsy moth climatic assessment model, with host species distributions, and climate (historical, present, and future). This integrated system was then used to evaluate climate change scenarios for native host species in Utah, with the result that risk of establishment will dramatically increase during the remainder of the 21st century under reasonable climate change scenarios. We then applied the risk assessment system to several case histories of detected gypsy moth introductions in Utah. These applications demonstrated the general utility of the system for predicting risk of establishment and for designing improved risk detection strategies.     

An investigation into the likely impact of oxy-coal retrofit on fire-side corrosion behavior in utility boilers

Real-time electrochemical measurements of corrosion rate were performed to evaluate the respective corrosion rates of one boiler waterwall material (SA210) and three boiler superheater materials (T22, P91 and 347H) while firing Utah Western bituminous, Illinois high-sulfur bituminous and Powder River Basin (PRB) sub-bituminous coals in a 1.5 MW pulverized coal-fired furnace. The raw average measured corrosion rates were very low, between 0.0003 and 0.016 mm/year (0.012 and 0.63 mils/year) for most materials under air- and oxy-fired conditions. For some high-sulfur conditions measured corrosion rates were as high as 0.72 mm/year (28 mils/year). Waterwall corrosion rates decreased consistently when converting from air- to oxy-firing while superheater corrosion rates generally increased, although they were less than twice the air-fired rate under most conditions. Corrosion rates for the lower alloyed materials (SA210 and T22) increased significantly during transients from reducing to oxidizing conditions. Measured increases in the corrosion rate of 347H material under high sulfur and low temperature conditions, and associated decrease in corrosion rate at higher temperatures on this alloy, were consistent with the formation of trisulphates in the superheater deposits. The increase of corrosion rate with increased metal temperatures was demonstrated, as was the consistently repeatable nature of the observed results.     

River Basin Export Reduction Optimization Support Tool; a tool to screen options for reducing nutrient loads while minimizing cost

Excess loading of nitrogen and phosphorus to river networks causes environmental harm, but reducing loads from large river basins is difficult and expensive. We developed a new tool, the River Basin Export Reduction Optimization Support Tool (RBEROST) to identify the least-cost combinations of management practices that will reduce nutrient loading to target levels in downstream and mid-network waterbodies. We demonstrate the utility of the tool in a case study in the Upper Connecticut River Basin in New England, USA. The total project cost of optimized lowest-cost plans ranged from $18.0 million to $41.0 million per year over 15 years depending on user specifications. Plans include both point source and non-point source management practices, and most costs are associated with urban stormwater practices. Adding a 2% margin of safety to loading targets improved the estimated probability of success from 37.5% to 99%. The large spatial scale of RBEROST, and the consideration of both point and non-point source contributions of nutrients, make it well suited as an initial screening tool in watershed planning.     

Minimum Wet‐Season Flows and Levels in Southwest Florida Rivers1

Abstract: Regulation of river flows can result in decreased stage fluctuations and alteration of inundation patterns of floodplain wetlands. However, floodplain inundation has historically not been addressed in most minimum flow determinations. Florida law requires the water management districts of the state to establish minimum flows and levels to protect water bodies from significant harm associated with water withdrawals. The Southwest Florida Water Management District utilizes a 15% reduction in habitat criterion as a threshold for defining significant harm to freshwater segments of rivers. Utilizing a multi‐parameter approach and different habitat measures for seasonal flow periods, the District has recommended minimum flow compliance standards for the Alafia, Myakka and middle Peace rivers. For the high‐flow period, the District utilized a 15% reduction in the number of days of floodplain inundation (a temporal loss) as a significant harm threshold. This approach yielded allowable flow reductions of 8% for the Alafia and Peace rivers during the high‐flow season and a 7% allowable reduction of natural flows on the Myakka River. Comparison of changes in flows associated with temporal and spatial loss thresholds indicated that flow reductions required to effect a 15% spatial loss of habitat on the Alafia, Myakka and middle Peace rivers are higher than those that would yield a 15% temporal loss. This indicates that with respect to natural flow protection, the District’s consideration of temporal reductions in habitat for establishing minimum river flows for seasonal high‐flow periods is more conservative than the use of a spatial loss criterion.     

Simplified method for the determination of acid-soluble sulfides in marine sediments

A simple, rapid method for the measurement of acid-soluble sulfides from marine sediments, in the range of 0 to 350 g sulfide, was developed. Using the mean of 4 replicates, the maximum sensitivity of the method is ±5.48 g. The method is based on iodometric back titration after the reaction of a standard iodine solution with the sulfide, which is precipitated on paper wicks as zinc, sulfide. The mean coefficient of variation, based on raw titration data, is 0.71% for aliquots from field samples, 0.41% for standards, and 0.21% for blanks. The method is used to compare zinc acetate-fixed subsamples, one group having been stored for 1 month in a refrigerator at 5°C and the other having been analyzed immediately after collection. No significant differences in sulfide content between subsamples, at the 95% confidence level, were noted.