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91.
Martin A. Stapanian David W. Shea 《The International journal of environmental studies》2013,70(1-2):45-56
The effects of Lignosite#rm lignosulfonate, a refined lignosulfonate product that is obtained from the sulfite pulping process, on growth and survival of plants were investigated. Following applications of 0, 7500, 15,000 and 22,500 cm3#shm2 to 32 plots within a forest plantation, the following were monitored: (1) live aboveground biomass of vascular plants, (2) growth of Douglar fir (Pseudotsuga menziesii) and (3) lignosulfonate migration through the soil profile. Live aboveground biomass of woody vegetation was not affected, and that of herbaceous plants was significantly decreased only at the two greatest application rates. Growth of the Douglas fir trees was not significantly affected. Lignosulfonates disappeared from the soil profile at the same rate regardless of initial concentration. Although it is not practical to use this material as a herbicide in western Washington, land application of lignosulfonates may be environmentally more attractive than traditional disposal methods. 相似文献
92.
The 1101 km length of the Andalusian coast (Spain) was assessed for coastal scenery at 45 specific locations. Selected areas covered resort (3), urban (19), village (8), rural (10) and remote (5) bathing areas. Scenery was analyzed for physical and human parameters via 26 selected parameters. These parameters were obtained by interviews of >500 people on European beaches. Each parameter was assessed via a one-to-five-point attribute scale, which essentially ranged from presence/absence or poor quality (1), to excellent/outstanding (5). Results were subsequently weighted by interviewing >600 bathing area users (not all 26 parameters have equal weight) and subjected to fuzzy logic mathematics in order to reduce recorder subjectivity. High weighted averages for attributes 4 and 5 (excellent/outstanding) reflected high scenic quality, vice versa for attributes 1 and 2. Sites were classified into five classes ranging from Class 1 sites having top grade scenery to Class 5, poor scenery. Seven sites each were found in Classes 1 and 2; 10 sites each in Classes 3 and 5; 11 sites in Class 4. The finest coastal scenery was found in remote areas whilst urban areas scored mainly as Class 3 or 4. Three out of the ten rural sites had Class 3 and 4 values assigned them whereas the rest scored as Class 1 and 2; village sites invariably had scores within Class 3 and 4. Of the three resort sites investigated, one scored as a Class 1 site, the others as Class 3. 相似文献
93.
Ancient semi-natural deciduous woodland is a rare and threatened habitat cited by the European Union's Habitats Directive (92/43/EEC). Current protection of this endangered habitat in the UK takes the form of site-specific reserve designations but, if the habitat is to be conserved and enhanced, a landscape-scale selective targeting system is required. In the absence of suitable species data, physical attributes of habitat patches are used as surrogate indicators of biodiversity. Using a land-use database held on a geographical information system, values of four abiotic criteria (patch area, patch shape, nearest-neighbour distance and surrounding land use) of 48 ancient semi-natural woodland patches in part of the Chiltern Hills Area of Outstanding Natural Beauty were calculated. In order to validate the findings, three lists of floral and faunal species, indicative of ancient semi-natural woodland, were compiled, and the patches ranked according to their alpha diversity using each list. Spearman's rank correlation coefficients were calculated for patch alpha diversity and patch area (0.322 to 0.482), patch shape (0.275 to 0.465) and nearest-neighbour distance ( - 0.092 to - 0.223). Multiple regression indicated that between 15 and 22% of the variation in alpha patch diversity was explained by the abiotic factors. It is suggested that spatial targeting at the landscape scale is a valuable approach to habitat conservation. 相似文献
94.
Caroline T.W. Chan 《Construction Management & Economics》2013,31(10):903-914
Estimation is the first step in the project development process. Information technology provides an efficient platform for estimators to obtain quotations and specifications for their bid estimates. However, in practice, project overhead estimation relies heavily on the professional judgement and intuition of the estimators. This reduces the overall accuracy and reliability of the bid and a better understanding of the factors affecting project overheads is fundamental before any improved estimating methods can be devised. Unfortunately, the published literature on this topic is very limited. Using exploratory factor analysis, we aim to bridge the current knowledge gap by highlighting the principal factors affecting project overheads. Questionnaires detailing 27 variables were sent to quantity surveying managers of large contractors in Hong Kong. Seventy-nine valid responses were analysed by exploratory factor analysis. From the results, eight factors were extracted with their latent properties identified with reference to the expert opinions collected from telephone interviews. The findings clarify some misconceptions about the factors affecting project overheads and provide useful evidence for practitioners and researchers to understand project overheads. Estimators who address the identified factors when assessing future project overhead costs can improve the accuracy of their cost estimates and project budgets. 相似文献
95.
96.
Ralph W. Pfouts 《Journal of the American Planning Association. American Planning Association》2013,79(2):64-69
Most central cities must at present bargain with other units of their regions and the nation for the residents and industry they need; and their bargaining power is so weak as to threaten their viability unless aid from state and federal governments is supplied. Both in order to serve the disadvantaged residents they do attract, and to cultivate their attractiveness to other residents and to industry, cities must re-define “urban renewal” as consisting of large investments in the development of human, land, and transportation potentialities. Such investments must, as all investments, come from “surpluses” which are controlled by the states and the nation, not the cities. 相似文献
97.
This study highlights the effect of membrane action in improving load carrying capacity of Profiled Steel Sheeting Dry Board (PSSDB) floor system. PSSDB system is a lightweight composite structural system composed of profiled steel sheeting and dry board, attached together by self-drilling and self-tapping screws. Many literatures have reported that restricting conventional slabs, such as reinforced concrete slab, at the supports against translation and/or rotation while it is subjected to vertical loading develops the compressive membrane action in the slab. The development of this phenomenon is considered in the PSSDB system with concrete infill for continuous and practical spans, with and without topping concrete. Previous authors’ experimentally verified non-linear finite element model for the PSSDB floor without topping was extended to parametrically predict the effect of different boundary conditions on the performance of the system for practical applications. It was revealed that preventing the in-plane movement of the slab ends improves the flexural rigidities of the slab up to more than three times when considering central deflection of serviceability limit state. This was observed when the deflection limit load of the fixed both end supports model was compared to the pin-roller support model. Moreover, the topping concrete enhances the applicability of the system in longer span and the developed compressive membrane action dramatically boosts the load carrying capacity of the slab with restricted translation and/or rotation of the slab ends. 相似文献
98.
A. N. Clarke W. W. Eckenfelder E. D. McMullen J. A. Roth B. A. Young 《Water research》1978,12(10):799-804
A continuous oxygen uptake meter or continuous respirometer was developed which produced a rapid and reliable response to systemic shocks. The respirometer basically is a 101. Plexiglas laboratory activated sludge unit with a variable volume air tight side car. The feed enters the completely mixed aeration basin and is pumped into the side car. The side car is the site of the oxygen uptake measurements as indicated by a continuously monitoring dissolved oxygen probe. The system was most sensitive to changes in influent concentrations when run at an F/M = 0.1. Response time for a change in DO of 0.1 ppm was less than 4 min. The continuous respirometer was tested employing both synthetic and raw industrial wastes. 相似文献
99.
Critical swimming velocities of Salmo gairdneri at 12°C were determined in different combinations of copper; pH and hardness. Measurements were made after exposure for 0.5, 5, 10, and 30 days. When copper was not applied, hardness, pH and exposure time had no appreciable effect on critical performance. Copper had the greatest effect on swimming performance at 5 days of exposure. At pH 7.5–8.0, recovery from the initial depression was complete after 10 days of exposure, but critical swimming performance did not return to control levels in pH 6.0 treatments. For any given hardness, copper had a greater effect on critical speed at low than at high pH. A given copper treatment had a more pronounced effect at low than at high hardness.No distinction could be made among total, soluble, or extractable copper but predicted concentrations of 6 specific cupric ions varied with pH and hardness. Of these copper species, only Cu2+ and CuOH+ were found to be related significantly to critical performance.Oxygen consumption of trout was determined in different combinations of copper and pH. In the presence of copper the maximum oxygen consumption decreased and the energy expenditure for a given swimming speed increased.The above observations are discussed in relation to reported toxic actions of copper. 相似文献
100.
Hasselbach L Ver Hoef JM Ford J Neitlich P Crecelius E Berryman S Wolk B Bohle T 《The Science of the total environment》2005,348(1-3):211-230
Heavy metal escapement associated with ore trucks is known to occur along the DeLong Mountain Regional Transportation System (DMTS) haul road corridor in Cape Krusenstern National Monument, northwest Alaska. Heavy metal concentrations in Hylocomium splendens moss (n = 226) were used in geostatistical models to predict the extent and pattern of atmospheric deposition of Cd and Pb on Monument lands. A stratified grid-based sample design was used with more intensive sampling near mine-related activity areas. Spatial predictions were used to produce maps of concentration patterns, and to estimate the total area in 10 moss concentration categories. Heavy metal levels in moss were highest immediately adjacent to the DMTS haul road (Cd > 24 mg/kg dw; Pb > 900 mg/kg dw). Spatial regression analyses indicated that heavy metal deposition decreased with the log of distance from the DMTS haul road and the DMTS port site. Analysis of subsurface soil suggested that observed patterns of heavy metal deposition reflected in moss were not attributable to subsurface lithology at the sample points. Further, moss Pb concentrations throughout the northern half of the study area were high relative to concentrations previously reported from other Arctic Alaska sites. Collectively, these findings indicate the presence of mine-related heavy metal deposition throughout the northern portion of Cape Krusenstern National Monument. Geospatial analyses suggest that the Pb depositional area extends 25 km north of the haul road to the Kisimilot/Iyikrok hills, and possibly beyond. More study is needed to determine whether higher moss heavy metal concentrations in the northernmost portion of the study area reflect deposition from mining-related activities, weathering from mineralized Pb/Zn outcrops in the broader region, or a combination of the two. South of the DMTS haul road, airborne deposition appears to be constrained by the Tahinichok Mountains. Heavy metal levels continue to diminish south of the mountains, reaching a minimum in the southernmost portion of the study area near the Igichuk Hills (45 km from the haul road). The influence of the mine site was not studied. 相似文献