A review on the use of waste glasses in the production of cement and concrete

The use of recycled waste glasses in Portland cement and concrete has attracted a lot of interest worldwide due to the increased disposal costs and environmental concerns. Being amorphous and containing relatively large quantities of silicon and calcium, glass is, in theory, pozzolanic or even cementitious in nature when it is finely ground. Thus, it can be used as a cement replacement in Portland cement concrete. The use of crushed glasses as aggregates for Portland cement concrete does have some negative effect on properties of the concrete; however, practicle applicability can still be produced even using 100% crushed glass as aggregates. The main concerns for the use of crushed glasses as aggregates for Portland cement concrete is the expansion and cracking caused by the glass aggregates. This paper summarizes the progresses and points out the directions for the proper uses of waste glasses in Portland cement and concrete.     

The legacy of Bhopal: The impact over the last 20 years and future direction

Chemical process safety was not a major public concern prior to 1984. As far as chemical hazards were concerned, public fears focused on disease (cancer) and environmental degradation. Even a series of major process incident tragedies did not translate into widespread public concerns about major incidents in chemical plants that might disastrously affect the public. This situation changed completely after the December 1984 disaster at the Union Carbide plant in Bhopal. Not only was the public's confidence in the chemical industry shaken, the chemical industry itself questioned whether its provisions for protection against major incidents were adequate.

The recognition of the need for technical advances and implementation of management systems led to a number of initiatives by various stakeholders throughout the world. Governments and local authorities throughout the world initiated regulatory regimes. Has all that has resulted from the legacy of Bhopal reduced the frequency and severity of incidents? How can we answer this question? As we move into more and more globalization and other complexities what are the challenges we must address? According to the authors, some of these challenges are widespread dissemination and sharing of lessons learned, risk migration because of globalization, changing workforce, and breakthroughs in emerging areas in process safety.     

Chemical modifications of groundwater contaminated by recharge of treated sewage effluent

Long-term monitoring of the chemical composition of recharge sewage effluent and associated contaminated groundwater from the Dan Region Sewage Reclamation Project shows, after 16 years of recharge operation, the presence of a distinct saline plume (up to 400 mg/l Cl), extending 1600 m downgradient in the Coastal Plain aquifer of Israel. The recorded electrolyte composition of groundwater in the vicinity of the recharge area reflects the variations in the compositions of the sewage effluents, as well as water-rock interactions induced by the recharge of treated sewage effluents. The original sewage composition was modified, particularly during early stages of effluent migration in the unsaturated zone, by cation-exchange and adsorption reactions. Since the soil sorption capacity is finite these reactions caused only limited modifications, and once the system reached a steady state the inorganic composition of the contaminated groundwater became similar to that of the recharge water. Decomposition of organic matter in the unsaturated zone resulted in CO₂ generation and dissolution of CaCO₃ minerals in the aquifer. It was shown that chemical and/or bio-degradation of organic matter takes place mainly in the unsaturated (vadose) zone. Hence, monitoring the efficiency of the vadose zone to retain contaminants is essential for evaluating the quality of groundwater since it was shown that organic compounds behave almost conservatively once the effluents enter and flow within the saturated zone.     

Factors influencing acquisition of ecological and exposure information about hazards and risks from contaminated sites

Considerable research indicates that a wide range of socio-economic factors influence attitudes and perceptions about environmental hazards and risks, and that social trust in those who manage a hazard is strongly correlated to judgements about risks and benefits. We suggest that there are three steps that lead to environmental risk perceptions: acquisition of information, interpretation and synthesis of different pieces of information, and understanding of that information in light of previous knowledge, perceptions, or attitudes. In this study we presented 211 college students in the sciences and non-sciences with ecological and exposure information using text, tables and maps to examine the factors that affect information acquisition and interpretation concerning ecological issues at a fictitious hazardous waste site. Students were allowed about an hour to read the materials and answer questions. The percent of students answering each question correctly varied from 4 to 82%, indicating that some questions were extremely difficult to answer. We attributed these differences to variations in the number of places information was presented (in text, tables, maps, or a combination) and the complexity of the information (how many pieces of information were required to answer the question correctly). The correlation between the number of students answering each question correctly and these combined measures (frequency, complexity) was −0.72. Thus, although there were differences in accuracy concerning ecological information as presented in this study, the major differences were accounted for by how the information was presented, and how much information was required. This suggests that risk communicators should carefully determine which ecological information is critical for the target audience, and ensure that it is presented several times (in different forms). That a lower percentage of people correctly answered questions that required synthesizing several pieces of information suggests that this complexity should be reduced where possible, or that the pieces of information should be tied clearly to the conclusion. Self-declaration of effort and perceptions of safety of the site did not markedly influence the relationship between accuracy, difficulty of finding information, and complexity of information. Other possible confounding variables (i.e., science vs non-science major) only accounted for about 27% of the variation in student’s overall score on ecological questions; age, ethnicity, and gender did not enter as significant variables. We cannot manage environmental hazards with appropriate stakeholder input unless we understand how to present environmental information to achieve a full understanding. Protection of human health and the environment requires that people understand ecological and exposure information, particularly on buffer lands.     

A robust nonparametric method for quantifying undetected extinctions

How many species have gone extinct in modern times before being described by science? To answer this question, and thereby get a full assessment of humanity's impact on biodiversity, statistical methods that quantify undetected extinctions are required. Such methods have been developed recently, but they are limited by their reliance on parametric assumptions; specifically, they assume the pools of extant and undetected species decay exponentially, whereas real detection rates vary temporally with survey effort and real extinction rates vary with the waxing and waning of threatening processes. We devised a new, nonparametric method for estimating undetected extinctions. As inputs, the method requires only the first and last date at which each species in an ensemble was recorded. As outputs, the method provides estimates of the proportion of species that have gone extinct, detected, or undetected and, in the special case where the number of undetected extant species in the present day is assumed close to zero, of the absolute number of undetected extinct species. The main assumption of the method is that the per‐species extinction rate is independent of whether a species has been detected or not. We applied the method to the resident native bird fauna of Singapore. Of 195 recorded species, 58 (29.7%) have gone extinct in the last 200 years. Our method projected that an additional 9.6 species (95% CI 3.4, 19.8) have gone extinct without first being recorded, implying a true extinction rate of 33.0% (95% CI 31.0%, 36.2%). We provide R code for implementing our method. Because our method does not depend on strong assumptions, we expect it to be broadly useful for quantifying undetected extinctions.     

Photochemistry of phenanthrene,pyrene, and fluoranthene in ice and snow

Although polycyclic aromatic hydrocarbons (PAHs) are common pollutants in snow, there is little quantitative data about their rates of photodegradation in this environment. To begin to address this gap, we have measured the degradation kinetics of phenanthrene, pyrene, and fluoranthene on ice, as these are the most abundant PAHs in arctic snow. Frozen aqueous solutions of individual PAHs, with and without added hydrogen peroxide (HOOH) as a source of hydroxyl radical (OH), were illuminated with simulated sunlight. For all three PAHs, direct photodecay is the main mechanism of degradation, while OH-initiated indirect photodegradation is a minor sink. Rate constants (±1 SE) for direct photodegradation extrapolated to midday, surface snow conditions at Summit, Greenland on the summer solstice are 3.8 (±0.8) × 10^?5, 28 (±3) × 10^?5, and 1.4 (±0.7) × 10^?5 s^?1 for phenanthrene, pyrene, and fluoranthene, respectively. Apparent quantum efficiencies for photodegradation with simulated sunlight were 3.8 (±0.8) × 10^?3, 4.3 (±0.5) × 10^?4, and 2 (±1) × 10^?5, respectively. Calculated PAH lifetimes in surface snow under Summit conditions are 1–19 h during mid-summer, but increase to >100 days in the dark winter. While the short photodegradation lifetimes in the summer suggest that there should be no appreciable PAH levels in this season, past measurements at Summit sometimes show significant levels of these PAHs in summer surface snow. This discrepancy is likely due to differences in PAH location between lab samples (where the PAHs are probably in quasi-liquid layers) and real snow (where PAHs are likely primarily associated with particulate matter).     

Monitoring of natural and synthetic hormones in a polluted river

Natural (estradiol, estrone, testosterone, estriol) and synthetic hormones (ethinylestradiol) are constantly excreted into the environment from human and animal sources but little is known of their transport. The purpose of this study was to determine how far along a 100 km river course that hormones could be detected after contamination with sewage effluent or fishpond effluent. Fourteen sites in the Lower Jordan River drainage were sampled (two sites above the sewage effluent contamination, eight sites below the contamination and four tributaries) before and after the dry season of 2002 (Spring and Fall). Samples were tested for testosterone, estrogen (estrone and estradiol combined), estriol, ethinylestradiol, ammonia and fecal coli. It was found that the fecal coli count dropped exponentially (from 250,000 to 60/100 ml3) and the ammonia dropped from 15 to less than 1mg/l over the initial 25 km stretch. Over the same stretch, the hormone values declined by half from their maximum values for testosterone (3.3 ng/l), estriol (8.8 ng/l), ethinylestradiol (6.1 ng/l), and estrogen (4.9 ng/l). From 67 to 100 km mark, testosterone (4.8 ng/l) and estrogen (2.4 ng/l) were still elevated while ethinylestradiol and estriol were >or=1.5 ng/l. The high level of testosterone and estrogen between 67 and 100 km marks was probably due to major discharge from fishponds between 23 and 27 km marks. Levels of ethinylestradiol above 1 ng/l, a level which can affect fish, was seen in 70% (12/16) of the samples tested. The data suggest that hormones in readily measured quantities can be transported considerable distances from the source of pollution.     

Effects of prolonged irrigation with treated municipal effluent on runoff rate

The use of domestic effluents for the irrigation of crops has been widespread in Israel for the past 30 years. The sodium adsorption ratio (SAR) of the standardized domestic effluents ranges between 4 and 6. According to the literature, when soils with SAR levels of 4 to 6 are exposed to direct raindrop impact they are subjected to enhanced aggregate disintegration, leading to sealing processes of the soil surface and subsequent increased runoff and soil erosion. However, these phenomena were not observed in the laboratory and field experiments of this study. On the other hand, a rapid decrease of the soil SAR to its initial values was observed, in laboratory and fieldwork, once the soil was subjected to a simulated rainstorm of distilled water (laboratory) or natural rainstorms (field plots). We can conclude that the process of SAR increase during irrigation with standardized effluent water is reversible. Further investigation in this direction can lead to recommendations regarding the necessary levels of domestic sewage water purification in correlation with soil types, climatic conditions, and hazards to tap water aquifers.     

Calibrate failure-based risk assessments to take into account the type of chemical processed in equipment

Currently, failure-based risk assessments in the process industry do not empirically take into account the type of chemicals processed in equipment, mainly because chemical-specific failure rate data barely exist. This paper suggests a methodology to calibrate failure-based risk assessment predicated on the chemical being processed in equipment. The methodology uses a data mining tool known as the association rule. Specifically, the lift association rule is utilized (the Lift Methodology). By extracting equipment failure information from incident databases based on the chemical involved in the process, the Lift Methodology leads to more accurate equipment-related risk assessment.     

Age and gender differences in conviction and crash occurrence subsequent to being directed to Iowa's driver improvement program

Introduction

This paper investigates potential gender and age differences in conviction and crash occurrence subsequent to being directed to attend Iowa's Driver Improvement Program (DIP).

Methods

Binary logit models were developed to investigate the factors that influence conviction occurrence after DIP by gender and age. Because of the low crash occurrence subsequent to DIP, association rules were applied to investigate the factors that influence crash occurrence subsequent to DIP, in lieu of econometric models.

Results

There were statistical significant differences by driver gender, age, and conviction history in the likelihood of subsequent convictions. However, this paper found no association between DIP outcome, crash history, and crash occurrence.

Impact on industry

Evaluating the differences in conviction and crash occurrence subsequent to DIP between female and male drivers, and among different age groups can lead to improvements of the effectiveness of DIPs and help to identify low-cost intervention measures, customized based on drivers’ gender and age, for improving driving behaviors.