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81.
To date, the results of studies which attempted to estimate residential water demand models have varied, but the source of these variations is not evident because the studies have applied different methodologies and data bases to different regions. The purpose of this paper is to develop models of residential water demand for watershed regions and test the null hypothesis that a single model is adequate to explain variations for all of the individual regions. Primary data collected from questionnaires and utility company records is used in a regression analysis to estimate a generalized water demand model for the state as well as one for each of the subregions. The null hypothesis is rejected which indicates that there are other factors which influence the demand for water and the use of a single model could result in biased estimates. 相似文献
82.
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
83.
A.?K.?RainaEmail author A.?Haldar A.?K.?Chakraborty P.?B.?Choudhury M.?Ramulu C.?Bandyopadhyay 《Bulletin of Engineering Geology and the Environment》2004,63(3):209-214
Ground vibration (Vmax) and air-overpressure/noise (p) are some of the negative effects of blasting. The associated human annoyance and complaints are expected to show an increasing trend in the future as there is no economically viable alternative to blasting in mines in India.A study of the human response to blasting in four mining localities across India has shown that the response is not simply political, as frequently assumed. It has been found that irrespective of those questioned, a basic concern for the safety of property was the main response. There was a greater response from the middle-aged and middle-educated while fewer women than men responded. Assuming that a 100% negative response from the inhabitants will translate into complaints, a methodology is suggested to take account of the human response criteria when considering blasting within 400 m of habitations. 相似文献
84.
The bioaccumulation potentials by aquatic biota from aqueous solution were determined for seven polycyclic aromatic hydrocarbons (PAH). The PAH were tested usingDaphnia pulex and consisted of the following compounds: naphthalene, anthracene, phenanthrene, pyrene, 9-methylanthracene, benz(a)anthracene and perylene. Bioaccumulation kinetics were described as a first order approach to equilibrium in a two-compartment model (water and Daphnia), using a two-stage technique to estimate uptake and elimination rates, while accounting for decreasing aqueous concentrations. Estimates of equilibrium concentration factors were obtained by two methods: (1) evaluating the kinetic model as t tends to infinity and (2) direct measurement of concentration factor at t =24 h.Estimations of equilibrium concentration factors obtained by the two methods were in good agreement, and increased dramatically with increasing molecular weight within the series of compounds. The calculated n-octanol-water partition coefficient was shown to be a good predictor of bioaccumulation potential of PAH in Daphnia. PAH were concentrated from a high of about 10,000-fold for benz(a)anthracene to a low of about 100-fold for naphthalene. 相似文献
85.
K. Weber 《Water research》1976,10(3):237-241
The decomposition of parathion (O,O-diethyl-O-p-nitrophenylthiophosphate) in seawater has been followed in the laboratory. The influence of temperature, pH, salinity, and particulate matter on the degradation time and products is shown. Chemical hydrolysis as well as biodegradation occurred. The ratio of the two depends on the pretreatment of the water. During chemical hydrolysis dearylation and dealkylation occur. Biodegradation was observed through the disappearance of the organic nitro compounds. Among the degradation products dealkylated parathion was found to be stable against further hydrolysis and microbial degradation under environmental conditions. 相似文献
86.
Guseva T. V. Tikhonova I. O. Tsevelev V. N. Shchelchkov K. A. Averochkin E. M. 《Glass and Ceramics》2022,78(9):397-401
Glass and Ceramics - A system for technological regulation of adverse environmental impacts (AEI) that is based on the best available technologies (BAT) was analyzed. The expediency of updating the... 相似文献
87.
Pyatigor A. D. Myshelovka L. V. Vokhmyanina K. A. Sotnikova V. S. Kubankina A. A. Grigor’ev Yu. V. 《Glass and Ceramics》2022,79(1-2):62-64
Glass and Ceramics - The results of experimental studies of the transmission of 12 and 15 keV electron beams through tapered glass macro-capillaries are presented. Measurements showed that there is... 相似文献
88.
Composites comprising Poly(Methyl Methacrylate) (PMMA) and CaCu3Ti4O12 (CCTO) via melt mixing followed by hot pressing were fabricated. These were characterized using X‐ray diffraction, thermo gravimetric, scanning electron microscopy, and Impedance analyzer for their structural, morphology, and dielectric properties. Composites were found to have better thermal stability than that of pure PMMA. The composite, with 38 Vol % of CCTO (in PMMA), exhibited remarkably low dielectric loss at high frequencies and the low frequency relaxation is attributed to the space charge polarization/MWS effect. Theoretical models were employed to rationalize the dielectric behavior of these composites. At higher temperatures, the relaxation peak shifts to higher frequencies, due to the merging of both β and α relaxations into a single dielectric dispersion peak. The AC conductivity in the high frequency region was attributed to the electronic polarization. POLYM. ENG. SCI., 54:551–558, 2014. © 2013 Society of Plastics Engineers 相似文献
89.
The three‐dimensional trajectories of polymer solution jets during the electrospinning of polymer nanofibers were experimentally investigated. Test conditions included water solutions of polyethylene oxide (PEO) with concentrations typical of those producing beaded nanofibers, driving voltages ranging from 5 kV to 15 kV to generate a single polymer jet and injection pressures ranging from 0 kPa to 55 kPa. The present holographic imaging setup resolved the spatial growth of the bending instabilities, which is beneficial for validating numerical models. The results also showed the bead formation on the polymer fiber in‐flight. POLYM. ENG. SCI., 54:1765–1773, 2014. © 2013 Society of Plastics Engineers 相似文献
90.
Sumit K. Kiran Vaughn M. Nace Maximilian A. Silvestri Keith A. Monk Jeremy Moloney Loreen Schmidt Edgar J. Acosta 《Journal of surfactants and detergents》2014,17(6):1193-1201
The partitioning of corrosion inhibitor (CI) products is a measure of their potential to protect oilfield pipelines. In this paper the hydrophilic–lipophilic deviation (HLD) model is first used to quantify their partitioning in terms of the characteristic curvature (C c,act) of a series of anionic (alkoxylated phosphate esters) and cationic (alkoxylated amines, aromatic amines, imidazoline acetates and quaternary amines) actives. This parameter is expressed over a range of pHs within which pipeline corrosion occurs. The HLD model is next used to predict the partitioning of each active from water into toluene at increased salinities. Linear mixing rules are lastly used to predict the characteristic curvature of Product A (C c,mix) as a function of the C c,act of a subset of actives. 相似文献