Chemical fluxes in time through forest ecosystems in the UK - Soil response to pollution recovery

Long term trend analysis of bulk precipitation, throughfall and soil solution elemental fluxes from 12 years monitoring at 10 ICP Level II forest sites in the UK reveal coherent national chemical trends indicating recovery from sulphur deposition and acidification. Soil solution pH increased and sulphate and aluminium decreased at most sites. Trends in nitrogen were variable and dependant on its form. Dissolved organic nitrogen increased in bulk precipitation, throughfall and soil solution at most sites. Nitrate in soil solution declined at sites receiving high nitrogen deposition. Increase in soil dissolved organic carbon was detected - a response to pollution recovery, changes in soil temperature and/or increased microbial activity. An increase of sodium and chloride was evident - a possible result of more frequent storm events at exposed sites. The intensive and integrated nature of monitoring enables the relationships between climate/pollutant exposure and chemical/biological response in forestry to be explored.     

Bipolar charged aerosol agglomeration and collection by a two-zone agglomerator

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Effect of CeO2 and Al2O3 on the activity of Pd/Co_3O_4/cordierite catalyst in the three-way catalysis reactions (CO/NO/CnHm)

The present article studies the effect of CeO₂ and Al₂O₃ on the activity of Pd/Co₃O₄/cordierite catalyst in conversion of NO, CO, C_nH_m. The catalysts were characterized by temperature programmed reduction with hydrogen, X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. It is shown that the effect of CeO₂ on the properties of Pd/Co₃O₄/cordierite catalyst depends on preparation method. The catalyst obtained by co-deposition of cerium and cobalt oxides has higher activity in CO oxidation (CO + O₂ and CO + NO) and total hexane oxidation (C₆H₁₄ + O₂). Such phenomenon is probably caused by more than stoichiometric amount of formed oxygen vacancies, an increase in both mobility of surface oxygen and dispersity of components in the catalytic composition. It is demonstrated that CeO₂ addition promotes the SO₂ resistance of Pd/Co₃O₄/cordierite. The second support decreases the activity of Pd/Co₃O₄/cordierite catalyst in the reactions of CO and C₆H₁₄ with oxygen because of CoAl₂O₄ formation.     

Characteristics and risks of drivers with low annual distance driven

OBJECTIVES: It has been noted by several authors that risk (defined only in terms of total expected numbers of crash involvements per total distance driven) paints a misleading picture of crash liability, particularly for the young and the old, as their high risk is associated with risky driving patterns typical of people who drive low annual kms. This article sets out to analyze these driving patterns of low-km drivers and to evaluate the risk of these patterns. As licensing programs tend to focus on young and old drivers, who tend to drive lower annual distances, income and employment data are also analyzed for low-km drivers. This is to provide a better picture for policy makers of the sort of people and the sorts of transportation requirements that their policies may affect. METHODS: Crash data and travel data were disaggregated by driver characteristics and by driving conditions (road type, day and night, weekend and weekday) and combined to form estimates of risk for typical driving patterns of driver groups. Characteristics of driving patterns and of the drivers themselves were derived for groups defined by age and by the amount of annual driving undertaken. RESULTS: Older drivers who drive less tend to have higher risk per km mainly due to their predominantly urban trips. Nevertheless, because older drivers on average manage to reduce their risk per distance driven by choosing driving patterns that are safer than the driving patterns of other age groups, the risk of older drivers as a group is not overestimated. CONCLUSION: Despite being quite different from one another, the low- and high-km driving patterns of younger drivers were found to impose identical risks.     

The role of relationships in understanding telecommuter satisfaction

Relationships are fundamental to organizational functioning, yet as telecommuting and other forms of virtual work become increasingly popular, research has not yet focused on how the virtual context might alter relationships so as to impact important work outcomes. This study therefore examines the role relationships play in mediating the link between the extent of telecommuting and job satisfaction. In doing so three fundamental types of relationships maintained by employees are investigated—those with managers, coworkers, and family. Regression analysis of field data from 294 telecommuting employees in a large telecommunications company revealed the anticipated inverted U‐shaped relationship, mediated by leader‐member exchange quality, team‐member exchange quality, and work‐family conflict. Copyright © 2006 John Wiley & Sons, Ltd.     

Characteristics of large cooking oil pool fires and their extinguishment by water mist

Large cooking oil pool fires, occurring in industrial oil cookers, present a severe hazard to food processing plants due to their size and the large amount of hot oil involved. This paper reports a series of full-scale fire experiments conducted in a large industrial oil cooker mock-up. The characteristics of large cooking oil pool fires and the effect of oil depth and hood position in the oil cooker on fire growth were studied. The use of water mist for extinguishing large oil pool fires and their extinguishing performance under different discharge pressure and with different types of water mist systems were investigated. Experimental results showed that the cooking oil underwent a substantial expansion in volume during heating. The fires developed quickly once the oil auto-ignited. The fire growth rate was affected by the oil depth in the pan and the hood position in the oil cooker. The water mist fire suppression systems effectively extinguished large cooking oil fires and prevented them from re-igniting. Their extinguishing performance was determined by the type of water mist system, discharge pressure and hood position in the oil cooker.     

On the response of 500 gal propane tanks to a 25% engulfing fire

This paper presents detailed data on the thermal response of two 500 gal ASME code propane tanks that were 25% engulfed in a hydrocarbon fire. These tests were done as part of an overall test programme to study thermal protection systems for propane-filled railway tank-cars.

The fire was generated using an array of 25 liquid propane-fuelled burners. This provided a luminous fire that engulfed 25% of the tank surface on one side. The intent of these tests was to model a severe partially engulfing fire situation.

The paper presents data on the tank wall and lading temperatures and tank internal pressure. In the first test the wind reduced the fire heating and resulted in a late failure of the tank at 46 min. This tank failed catastrophically with a powerful boiling liquid expanding vapour explosion (BLEVE). In the other test, the fire heating was very severe and steady and this tank failed very quickly in 8 min as a finite rupture with massive two-phase jet release. The reasons for these different outcomes are discussed. The different failures provide a range of realistic outcomes for the subject tank and fire condition.     

On the thermal rupture of 1.9 m propane pressure vessels with defects in their thermal protection system

This paper describes the results from a series of fire tests that were carried out to measure the effect of defects in thermal protection systems on fire engulfed propane pressure vessels.

In North America thermal protection is used to protect dangerous goods rail tank-cars from accidental fire impingement. They are designed so that a tank-car will not rupture for 100 min in a defined engulfing fire, or 30 min in a defined torching fire. One common system includes a 13 mm blanket of high-temperature ceramic fibre thermal insulation covered with a 3 mm steel jacket. Recent inspections have shown that some tanks have significant defects in these thermal protection systems. This work was done to establish what levels of defect are acceptable from a safety standpoint.

The tests were conducted using 1890 l (500 US gallon) ASME code propane pressure vessels (commonly called tanks in the propane industry). The defects tested covered 8% and 15% of the tank surface. The tanks were 25% engulfed in a fire that simulated a hydrocarbon pool fire with an effective blackbody temperature of 870 °C.

The fire testing showed that even relatively small defects can result in tank rupture if the defect area is engulfed in a severe fire, and the defect area is not wetted by liquid from the inside. A wall failure prediction technique based on uniaxial high-temperature stress rupture test data has been developed and agrees well with the observed failure times.     

Effectiveness of a Light-Weight Ice-Vest for Body Cooling While Wearing Fire Fighter’s Protective Clothing in the Heat

The aim of the study was to examine the effects of wearing an ice-vest (ca 1 kg) on physiological and subjective responses in fire fighters. The experiments were carried out on a treadmill in a hot-dry environment. The physical cooling effect of the ice-vest was measured with a thermal manikin. The ice-vest effectively reduced skin temperatures under the vest. On average, heart rate was 10 beats/min lower, the amount of sweating was reduced by 13%, and subjective sensations of effort and warmth were lower during work with the ice-vest compared to work without it. Thermal manikin tests indicated that the useful energy available from the vest for body cooling was rather high (58%). In conclusion, the ice-vest reduces physiological and subjective strain responses during heavy work in the heat, and may promote efficient work time by 10%.     

Child Abuse Investigation: Police Officers and Secondary Traumatic Stress

Child protection is an area of police work which has expanded in the last decade, leading to an increase in the number of police officers working in departments which specialise in investigating cases of child abuse. Police officers in this field may be at greater risk of experiencing secondary traumatic stress but there remains a paucity of research in this area of policing. Analogies can be drawn to existing research in policing and with social service workers involved in child protection. The paper finishes off with implications for police forces to ensure safe working environments and appropriate counselling for employees.