Nuclear power: the case for a long term policy

The present rapid expansion of the nuclear power programme is based largely on slightly enriched thermal reactor types with poor plutonium production, and could exhaust the rich uranium reserves well before the end of the century, whilst producing an inadequate plutonium inventory for a future fast breeder programme. A more gradual expansion of the thermal reactor programme based on “near‐breeder” reactors would extend the rich reserves to the year 2000 and build up an adequate plutonium inventory for a significant fast breeder programme, with the possibility of introducing the thorium fuel cycle early in the 21st century.     

In situ relationships between spatio-temporal variations in diuron concentrations and phototrophic biofilm tolerance in a contaminated river

Microbial biofilms are useful indicators for monitoring the ecological state of rivers. When assessing the effects of toxicants on microbial communities in natural ecosystems, special attention must be paid to the distinction between such effects and those resulting from other environmental variables. The pollution-induced community tolerance (PICT) approach offers the means to partially isolate effects of individual toxicants within a complex ecosystem by studying shifts in community sensitivity. To validate PICT for site-specific risk assessment, we investigated how closely diuron tolerance acquisition by photoautrophic biofilm communities could reflect their previous in situ exposure to this herbicide. To this end, a field survey was conducted for 9 months in a French river contaminated by diuron inputs from adjacent vineyards. Spatio-temporal variations in diuron tolerance capacities of photoautotrophic communities were estimated monthly using short-term photosynthetic bioassays. The biological survey was coupled with intensive physico-chemical monitoring to analyze the environmental factors influencing tolerance induction. We revealed a possible influence of three co-varying environmental variables (nitrates, conductivity and temperature), but statistical analysis clearly demonstrated that the main factor explaining variation in diuron sensitivity was the mean in situ diuron exposure level during biofilm colonization periods. A remarkable exponential correlation between EC₅₀ values and in situ diuron concentrations (R² = 0.90, p < 0.0001) was recorded, confirming that PICT can be a powerful tool for the environmental monitoring of rivers.     

Impact of physico‐chemical parameters on the microbial population and its nature in a major retting zone of Kerala

As part of an environmental abatement programme, through the application of bioremediation in the retting zones of Kerala, a microbiological survey was conducted during March 1999 in the Kadinamkulam kayal, a major retting zone in Kerala. Some selected physico‐chemical parameters were also analysed to assess the water quality in the context of retting activity. Comparatively low dissolved oxygen content coupled with high hydrogen sulphide observed at Stations 1 and 2 can be attributed to retting. Salinity distribution is of the mixohaline nature. Pseudomonas sp., E. coli and other coliform groups were found to be present in the area. Of these the most dominant was Pseudomonas sp. and hence its nature and plasmid profile were also studied. The study indicates an environmental degradation in the area, and the possibility of hotspots of pollution in the backwater biotopes in the State.     

Evaluation of depth-dependent porosity and bulk modulus of a shear using permeability–depth trends

Both porosity and deformation properties of porous media are dependent on stress. For geological media, the stress-dependent porosity and deformation properties can be shown to be depth related. Unfortunately, both in situ porosity and in situ deformation properties are difficult to measure. In the current study, a method is developed to evaluate the changes in porosity and bulk modulus with depth by using in situ measurements of permeability, which can be easily obtained by employing packer tests. In the case study, the change in permeability of a shear in the Baihetan hydropower station in Southwest China is estimated. Then, the permeability–depth correlation is utilized to calculate the porosity and the bulk modulus at different depths. The results clearly show that the porosity decreases with depth while the bulk modulus increases with depth. Based on the proposed model, the bulk modulus is calculated to increase from 4–6 MPa on the ground surface to 18–30 MPa at the depth of 160 m. The Young's modulus of the shear estimated with this depth-dependent bulk modulus is consistent with in situ measurement.     

Response of Scots pine (Pinus sylvestris L.) to stress induced by different types of pollutants – testing the fluctuating asymmetry

Damage caused to pine forests by industrial pollution is observed even several decades after emissions have stopped down. A simple morphological feature – the leaf fluctuating asymmetry – was used for assessing the condition of Scots pine (Pinus sylvestris) stands growing in a heavily degraded area. In 2011, a study was performed on the developmental instability of needles in four naturally reforested Polish populations of P. sylvestris. Studies were conducted within the protective zone at a zinc smelter, a copper smelter, a cement plant and train tracks. All selected areas manifested a high extent of anthropogenic pollution‐induced environmental degradation until the end of the 90s. Currently, a reduced level of environmental pollution is recorded at these sites. Control group was a natural population of Scots pine from the region of National Park of Wielkopolska. The results confirm the usefulness of fluctuating asymmetry as a highly sensitive indicator of non‐specific stress. Also, it was shown that in areas degraded by human activity, poor condition of Scots pine persists that the stress factor has been eliminated. This tendency occurs particularly to areas contaminated by heavy metals.     

The use of bromophenol blue as a tracer in sewage works

A reliable method for the quantitative assessment of water mixing in sewage works is presented. Using a rapid visible-spectroscopic technique to assay Bromophenol Blue, both laboratory and in situ adsorption/degradation studies are presented which confirm that this dye may be used quantitatively in tracer experiments.     

Review of the impact of the 1999 Water Regulation in reducing Cryptosporidium contamination risk in groundwater public supplies

In 2000, the UK introduced a Cryptosporidium oocyst monitoring programme for groundwater public supplies as a consequence of a 1999 amendment to statutory water quality regulations in England and Wales. The programme, which is ongoing and was estimated to have cost c. £12 million (€17.4 million) by the end of 2005, has accumulated the largest and most comprehensive array of data on the presence of oocysts in raw groundwater in the UK to date, with 90 water treatment works subjected to continuous monitoring at one time or another between 2000 and 2005. The programme was preceded by a scrutiny of the future of over 180 groundwater supplies identified as significantly at risk by the 19 water utilities concerned. The results of this process and of the monitoring programme up to 2005 are examined and critically reviewed.     

Contribution of in situ and laboratory investigations for assessing seismic vulnerability of existing bridges

This work describes the main results of an in situ experimental campaign carried out in the context of the seismic assessment of 71 existing road bridges as representative of the main structural typologies located in the Veneto region and pertaining to the regional roadway managing authority Veneto Strade SpA. An initial in situ and laboratory experimental campaign on basic materials and an overall geometrical survey were carried out for each bridge, using different tests according to the construction typologies, with the aim of characterising the main mechanical parameters of the significant structural elements. Structural assessment has been subsequently carried out according to the parameters derived from the above campaign and the design ground motion action. The results have been compared with those deriving from a preliminary analysis conducted on the basis of some assumptions on materials’ mechanical characteristics related to the original design documents and the construction practice at the time of the structures’ edification. This comparative analysis could give some insights on appropriate and rational planning of inspections on existing bridges and reliability of basic assumptions for their seismic assessment.     

Direct measurement of oxygen in river substrates

A study was conducted to establish if river substratum dissolved oxygen (DO) could be measured directly. Hitherto, such measurements have been carried out by proxy and indirect methods or by direct methods following installation of cores/tubes into the streambed. Redox potential (Eh) readings were also taken at most of the sites for comparison. The overall conclusion is that a reliable, off‐the‐shelf instrumental method of directly measuring DO in river substrates has been tested in laboratory and field conditions. The Eh meter, per contra, did give aberrant results for some measurements particularly in the field but had the advantage of a slimmer probe for easier penetration into substrata. The measurement technique, to determine river interstitial sediment O₂, is a simple and quick direct in situ method that produces reliable results.     

The effect of ventilation on indoor exposure to semivolatile organic compounds

A mechanistic model was developed to examine how natural ventilation influences residential indoor exposure to semivolatile organic compounds (SVOCs) via inhalation, dermal sorption, and dust ingestion. The effect of ventilation on indoor particle mass concentration and mass transfer at source/sink surfaces, and the enhancing effect of particles on mass transfer at source/sink surfaces are included. When air exchange rate increases from 0.6/h to 1.8/h_, the steady‐state SVOC (gas‐phase plus particle phase with log K_OA varying from 9 to 13) concentration in the idealized model decreases by about 60%. In contrast, for the same change in ventilation, the simulated indoor formaldehyde (representing volatile organic compounds) gas‐phase concentration decreases by about 70%. The effect of ventilation on exposure via each pathway has a relatively insignificant association with the K_OA of the SVOCs: a change of K_OA from 10⁹ to 10¹³ results in a change of only 2–30%. Sensitivity analysis identifies the deposition rate of PM_2.5 as a primary factor influencing the relationship between ventilation and exposure for SVOCs with log K_OA = 13. The relationship between ventilation rate and air speed near surfaces needs to be further substantiated.     

In situ strength criteria for tunnel design in highly-stressed rock masses

The selection of rock mass strength parameters and the approach to assessing the mechanical and thermal-mechanical rock mass behaviour around tunnels are important aspects of designing underground openings for a spent nuclear fuel waste repository. This paper demonstrates how strength criteria based on in situ observations can be used to design stable underground openings in rock masses subjected to adverse stress conditions. The findings are based upon work conducted at AECL’s Underground Research Laboratory (URL) regarding rock mass strength around tunnels in sparsely fractured granite.     

Practice-based learning in construction projects: a literature review

Construction project managers often face problems when trying to change work practices. Management research addresses these problems by offering stylized and abstract models; unfortunately, they may say little about the actual work practices that managers want to change. Practice theory offers an alternative way to address practice-related managerial problems, arguing that learning is a central enabler of performing practices. While some early research on practice-based learning in construction management exists, an understanding of how this theory has been applied is lacking. To address this limitation, a systematic literature review of 15 published construction management articles was conducted, the articles being divided into five practice-related analytical categories: participation, context, meaning production, power and becoming a practitioner to identify the areas of theory discussed. Participation and context were discussed more in the published articles than meaning production, power and becoming a practitioner, which might suggest that the latter categories offer more possibilities for future research. Further, the articles were analysed through a Lakatosian research programme lens, showing that a progressive research programme exists in practice-based studies in construction management. These findings provide avenues for future construction management studies seeking to apply practice-based learning theory to understand learning in construction projects better.     

Distribution and geochemical behaviour of anionic surfactants determined as ethyl violet active substances in Lake Biwa,Japan

The distribution and geochemical behaviour of anionic surfactants (AS) determined as ethyl violet active substances (EVAS) were studied in Lake Biwa, Japan. We determined the vertical distributions of dissolved EVAS (DEVAS), suspended particulate EVAS (PEVAS), particulate organic carbon (POC) and the PEVAS/POC ratio. Statistical analyses conducted using plots of PEVAS versus POC and PEVAS/ Chlorophyll‐a (Chl‐a) versus POC/Chl‐a revealed that the distributions of DEVAS and PEVAS were affected by the concentrations of freshly produced POC and aged POC and by the pH of the lake water. Adsorption and desorption of EVAS onto the POC phase were found to be important mechanisms regulating the distribution and environmental/geochemical behaviour of EVAS in the lake. The organic carbon‐normalized particle–water‐partitioning coefficient, K_oc, for EVAS was also estimated and compared with that for nonylphenol.     

Automatic Detection of Deficient Video Log Images Using a Histogram Equity Index and an Adaptive Gaussian Mixture Model

Abstract: Video log images are often used by transportation agencies to manually or automatically extract roadway infrastructure information, including roadway geometry, signs, etc. Poor‐quality images, especially those having illumination‐related deficiencies caused by color corruption with a plain‐like grayscale histogram, sun glare, or darkness problems, are unacceptable and need to be identified. Manually reviewing the tens of millions of video log images for quality control is labor intensive and time‐consuming, so there is a need to develop automatic video log image quality control procedures. The contribution of this article is that it formulates a new problem of roadway video log image quality control and then proposes a reasonable solution to address this problem in the hope that it will motivate the development of new algorithms by other researchers. For the first time, an algorithm using a Histogram Equity Index (HEI) and an adaptive Gaussian Mixture Model is proposed to address the video log image quality issue by automatically detecting illumination‐related deficiencies. The Alberta Department of Transportation provided 15,489 video log images to test the proposed algorithm. Test results show that the developed algorithm can detect illumination‐related video log image deficiencies with a false positive rate of 4%, 3%, and 12%; a false negative rate of 15%, 17%, and 19% for plain‐like color corruption, dark, and sun glare conditions, respectively; computation time is 0.1 second/image. The proposed algorithm could potentially be used to improve video log image data quality control.     

A simplified method for instability and second‐order load effects of framed structures: Story‐based approach

Several building codes such as ANSI/AISC 360‐16 and EC3 EN 1993‐1‐1 require the use of a proper design method to consider instability and second‐order load effect problems for individual system elements and the entire structural system. Various methods are available to assess stability. All of these methods should consider P‐Δ and P‐δ effects (second‐order effects). The following calculation procedures are presented in this study: (a) a simplified method is developed for P‐Δ and P‐δ analysis in regular frames under the effect of constant axial loads to obtain story drifts and end moments; (b) this method can be applied to an entire building or any individual story, that is, story‐based design is possible; and (c) column effective length factors are obtained for individual columns. In addition, design tables are presented.     

In situ feeding assay with Gammarus fossarum (Crustacea): Modelling the influence of confounding factors to improve water quality biomonitoring

In situ feeding assays implemented with transplanted crustacean gammarids have been claimed as promising tools for the diagnostic assessment of water quality. Nevertheless the implementation of such methodologies in biomonitoring programs is still limited. This is explained by the necessity to improve the reliability of these bioassays. The present study illustrates how modelling the influence of confounding factors could allow to improve the interpretation of in situ feeding assay with Gammarus fossarum. We proceeded in four steps: (i) we quantified the influence of body size, temperature and conductivity on feeding rate in laboratory conditions; (ii) based on these laboratory findings, we computed a feeding inhibition index, which proved to be robust to environmental conditions and allowed us to define a reference statistical distribution of feeding activity values through the data compilation of 24 in situ assays among diverse reference stations at different seasons; (iii) we tested the sensitivity of the feeding assay using this statistical framework by performing 41 in situ deployments in contaminated stations presenting a large range of contaminant profiles; and (iv) we illustrated in two site-specific studies how the proposed methodology improved the diagnosis of water quality by preventing false-positive and false-negative cases mainly induced by temperature confounding influence. Interestingly, the implementation of the developed protocol could permit to assess water quality without following an upstream/downstream procedure and to compare assays performed at different seasons as part of large-scale biomonitoring programs.     

Impact of asthma,exposure period,and filters on human responses during exposures to ozone and its initiated chemistry products

The impact of asthma, exposure period, and filter condition downstream of the mixing box of air‐conditioning system on building occupants' perceptual response, work performance, and salivary α‐amylase secretion during exposures to ozone and its initiated chemistry products is studied. The experiments were conducted in a field environmental chamber (FEC) (240 m³) simulating an office environment. Experiments were conducted during periods when the air‐handling system operated with new or used pleated panel filters at constant recirculation (7/h) and ventilation (1/h) rates. Average ozone and secondary organic aerosols (ozone‐initiated chemistry products) measured during non‐asthmatic and asthmatic subjects' 3‐h exposures in the FEC were in the ranges approximately 20–37 ppb and approximately 1.6–3 μg/m³, respectively. Asthmatic subjects' perceived odor intensity and sensory (eye, nose, and throat) irritation ratings were generally lower than those of non‐asthmatic subjects, possibly explaining why asthmatic subjects accept perceived air quality more than non‐asthmatic subjects. However, asthmatic subjects' perceived physiological‐like symptom ratings (flu, chest tightness, and headache) and concentrations of secreted salivary α‐amylase were generally higher than those of non‐asthmatic subjects. Asthmatic subjects had significantly lower accuracy than non‐asthmatic subjects in a task that required higher concentration although they had higher work speed. Filter condition did not make any significant difference for subjects' responses.     

Seasonal abundance,growth, feeding and age composition of flounder (platichthys flesus (l.)) populations of the severn estuary and bristol channel

Between 1972‐1977 flounders (Platichthys flesus L.) have been collected in weekly samples from the trash bins of the Oldbury‐on‐Severn nuclear power station on the inner estuary. Other occasional samples have also been taken from the nearby Berkeley power station as well as from Hinkley Point power station and Barnstaple Bay on the outer estuary and Bristol Channel. These collections have enabled studies to be made of seasonal and annual changes in relative abundance age composition, growth rates, diet and feeding habits.     

The Argentine radioactive waste respository: Basic criteria,preliminary siting and design conceptual basis

At the end of the seventies. The Argentine authorities decided to explore alternatives for disposing of the high-level radioactive wastes that would eventually be generated by the country's nuclear programme. This programme involves nuclear power reactors that will generate an integrated electrical energy of a fraction of a terawatt year by the end of the century (1). The country's programme also foresees the reprocessing of the spent fuel. The paper describes the basic criteria adopted by the Argentine authorities for the disposal of high-level wastes. On the basis of these criteria. a site in stable, unfractured granite was selected for detailed studies, near Gastre. Province of Chubut, out of about 200 potential sites. This site has been thoroughly investigated and its suitability has been validated. On the other hand, work has progressed on the design of the future repository.     

Role of solar agricultural-drying in developing countries

The Swedish Dower system is today based on hydro power (production 65 TWh/year) and nuclear power (production 55 TWh/year from 1986). Small amount of oil and gas is used for power production during peak periods.

The Swedish Parliament decided in 1980, after a consultative referendum, that all nuclear reactors will be closed between 1997 and 2010. In that perspective several new technologies are possible to use for power production. One interesting possibility is photovoltaic power production.

The objective of the paper is to analyse conditions for the use of photovoltaics in the Swedish power system.

The cost for electricity from photovoltaic power plants is calculated from cost goals in the United States photovoltaic development programme. Different costs during construction and operation are added. The capital costs are calculated for a real discount rate of 4% and the lifetime for the plant is assumed to be 30 years.

The receipts for photovoltaics are calculated from long run marginal revenues (power values) at year 2010.

The calculations give following results. If the lower cost goal for late 1990s is achieved, then electricity from photovoltaic power plants in Sweden will cost 3.6 pence/kwh (40 öre/kwh). The higher cost goal for 1990s results in an energy cost of 4.6 pence/kwh (51 öre/kWh). The cost for electricity from photovoltaic power plants will be the same as the cost for electricity from coal-fired power plants if the coal price rises from UK £ l.3/GJ during 1983 to UK £3.4–4.5/GJ around the decade 2000–2010.