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1.
Effluent sludge from an anaerobic digester was used as a source of nitrogen, phosphate, sulfur, and other nutrients in the culture medium of ethanol production by the yeast Saccharomyces cerevisiae. Several pretreatments (mechanical, chemical, thermal, and thermo-chemical) were performed on the anaerobic digested sludge (ADS) to make the nutrients accessible to the yeast cells. Preliminary experiments revealed that S. cerevisiae is not able to assimilate the carbon content of the ADS. However, when glucose was added to the medium, ethanol production was observed. The yield of ethanol using untreated ADS was only 10 % of the theoretical yield, but alkaline pretreatment improved it up to 43 %. By separating the hydrolysate of alkaline-treated ADS from the suspended solids, the ethanol yield from the supernatant was further improved up to 65 % of theoretical yield. Alkaline-treated ADS exhibited competitive performance with the mixture of yeast extract and mineral salts in ethanol fermentation.  相似文献   

2.
We have obtained the stellar velocity dispersion in three mutually perpendicular directions in the halos and cores of clusters as a function of time for several non-stationary open-cluster models. During the dynamical evolution of the open-cluster models, the velocity dispersions undergo oscillations that do not decay during 5–10 violent-relaxation timescales, τ vr . We estimated the time for synchronization of the rotation of the open-cluster models and their motion around the center of the Galaxy, t s , which, depending on the model parameters, is t s ? (5–27)τ vr . Synchronization mechanisms for the models are discussed. The disruption of the systems in the force field of the Galaxy is strongly affected by tidal friction. We have also estimated the time for the formation of a spherical stellar-velocity distribution in the cluster models, t σ ? (6 ? 25)τ vr . The impact of instability in the stellar motions in a cluster on the formation of a spherical velocity distribution in the open-cluster models is discussed. We have noted a tendency for a weakening of the dependence of the coarse phase density of the cluster on small initial perturbations of the stellar phase coordinates in the model cluster cores for times about five times longer than the violent-relaxation time.  相似文献   

3.
A technique for IR spectroscopic determination of the total nitrogen content N S in the form of A-and B 1-defects is suggested. It provides for the computer processing and decomposition of IR spectra into constituent bands, calculation of the total absorption band area S N and individual areas S A and S B1 and their normalization with respect to the total area of the diamond intrinsic absorption S 0, with the normalization coefficients K S , K A , and K B1 being calculated. Based on the analysis of the IR spectra of 60 octahedral diamond crystals from the Mir and Yubileinaya pipes (Sakha-Yakutiya), the empirical functions N S = 911.85 K S 0.9919 ppm (R 2 = 0.9859), N A = 1185.6 K A 1.1511 ppm (R 2 = 0.8703), and N B1 = 911.85 K S 0.9919 ? 1185.6 K A 1.1511 ppm have been defined.  相似文献   

4.
The Al-rich region of the CaO-MgO-Al2O3-SiO2 system was experimentally studied at pressures of 1.0–2.8 GPa and temperatures of 1300–1535°C. The slopes of the lines of the monovariant reactions An + Sp = Cpx + Cor + (Ga) and L = Cpx + Ga + Cor + Sp and the compositions of the phases involved in these reactions are determined. The results are utilized in the topological analysis of the aluminous region of the CaO-MgO-Al2O3-SiO2 system. On this basis, the principal structure of the phase diagram is analyzed, and a phase diagram is constructed for the junction region of the quaternary system and the CaO-Al2O3-SiO2 ternary system. A continuous series of the monovariant eutectic: L = Cpx + Opx + Fo + An, L = Cpx + Opx + An + Sp, L = Cpx + (Ga) + An + Sp, L = Cpx + Cor + (Ga) + An, L = An + Ga + Cpx + Ky and L = Ga + Cpx + Ky + Qz is examined within the pressure range from atmospheric to 3.0 GPa and higher. Analogous “telescoped” eutectic series are of fundamental character for interpreting the evolution of magmatic melts. A physicochemical model is suggested for the evolution of magmatic melts that produce rocks of the calc-alkaline series, with this model underlain by the fact that a change in the composition of magmatic melt at a pressure decrease should correspond to the minimum melting temperatures, i.e., to melts in the fundamental series of eutectic reactions. The comparison of our physicochemical model and rocks of the calc-alkaline series shows that the compositions of rocks of the calc-alkaline series are close to the compositions determined for the eutectic equilibria, and the mineralogical composition of xenoliths and megacrysts in volcanic and dike varieties of the rocks are similar to the subsolidus phases of the established fundamental eutectic system.  相似文献   

5.
The excitation of methanol in the absence of external radiation is analyzed, and LTE methods for probing interstellar gas considered. It is shown that rotation diagrams correctly estimate the gas kinetic temperature only if they are constructed using lines whose upper levels are located in the same K-ladders, such as the J0?J?1E lines at 157 GHz, the J1?J0E lines at 165 GHz, and the J2?J1E lines at 25 GHz. The gas density must be no less than 107 cm?3. Rotation diagrams constructed from lines with different K values for their upper levels (e.g., 2K?1K at 96 GHz, 3K?2K at 145 GHz, 5K?4K at 241 GHz) significantly underestimate the temperature, but enable estimation of the density. In addition, diagrams based on the 2K?1K lines can be used to estimate the methanol column density within a factor of about two to five. It is suggested that rotation diagrams should be used in the following manner. First, two rotation diagrams should be constructed, one from the lines at 96, 145, or 241 GHz, and another from the lines at 157, 165, or 25 GHz. The former diagram is used to estimate the gas density. If the density is about 107 cm?3 or higher, the latter diagram reproduces the temperature fairly well. If the density is around 106 cm?3, the temperature obtained from the latter diagram should be multiplied by a factor of 1.5–2. If the density is about 105 cm?3 or lower, then the latter diagram yields a temperature that is lower than the kinetic temperature by a factor of three or more, and should be used only as a lower limit for the kinetic temperature. The errors in the methanol column density determined from the integrated intensity of a single line can be more than an order of magnitude, even when the gas temperature is well known. However, if the J0?(J ? 1)0E lines, as well as the J1?(J ? 1)1A+ or A? lines are used, the relative error in the column density is no more than a factor of a few.  相似文献   

6.
The results of hydrodynamical calculations of radially pulsating helium stars with masses 0.5M⊙≤M≤0.9M⊙, bolometric luminosities 600L⊙≤5×103L⊙, and effective temperatures 1.5×104 K≤Teff≤3.5×104 K are presented. The pulsation instability of these stars is due to the effects of ionization of iron-group elements in layers with temperatures T～2×105 K. The calculations were carried out using opacities for the relative mass abundances of hydrogen and heavy elements X=0 and Z=0.01, 0.015, and 0.02. Approximate formulas for the pulsation constant Q over the entire range of pulsation instability of the hot helium stars in terms of the mass M, radius R, effective temperature Teff, and heavy-element abundance Z are derived. The instability of BX Cir to radial pulsations with the observed period Π=0.1066 d occurs only for a mass M≥0.55M⊙, effective temperature Teff≥23000 K, and heavy-element abundance Z≥0.015. The allowed mass of BX Cir is in the range 0.55M⊙≤M≤0.8M⊙, which corresponds to luminosities 800L⊙≤M≤1400L⊙ and mean radii 1.7R⊙?R?2.1R⊙.  相似文献   

7.
We analyze three-phase flow of immiscible fluids taking place within an elementary capillary tube with circular cross-section under water- and oil-wet conditions. We account explicitly for momentum transfer between the moving phases, which leads to the phenomenon of viscous coupling, by imposing continuity of velocity and shear stress at fluid-fluid interfaces. The macroscopic flow model which describes the system at the Darcy scale includes three-phase effective relative permeabilities, K i j,r , accounting for the flux of the ith phase due to the presence of the jth phase. These effective parameters strongly depend on phase saturations, fluid viscosities, and wettability of the solid matrix. In the considered flow setting, K i j,r reduce to a set of nine scalar quantities, K i j,r . Our results show that K i j,r of the wetting phase is a function only of the fluid phase own saturation. Otherwise, K i j,r of the non-wetting phase depends on the saturation of all fluids in the system and on oil and water viscosities. Viscous coupling effects (encapsulated in K i j,r with i ≠ j) can be significantly relevant in both water- and oil-wet systems. Wettability conditions influence oil flow at a rate that increases linearly with viscosity ratio between oil and water phases.  相似文献   

8.
Water inflow into deep excavations is a key parameter in the evaluation of environmental impact, and a simplified method is needed to calculate the inflow with adequate accuracy, especially for a deep excavation with a cutoff wall around it. This paper presents a model for calculating inflow based on the method of fragments, assuming two-dimensional sectional flow. The effects of cutoff wall thickness (w), wall penetration, and excavation width on the inflow are well considered in this model. Explicit formulas for the form factor are given. The accuracy and scope of this method are discussed. The method can be applied in both flooding and no flooding cases. Extensive verification shows that, for the flooding case and when one of four conditions is satisfied, the error of the proposed method will be within 10%. These conditions are b/d?≥?0.8 or w/d?≥?0.03 or s/d?≥?0.2 or s1/d?≥?0.2, for which b is the half width of the excavation, d is the thickness of the soil layer underlying the wall, and s and s1 are the wall penetration depths on the non-excavation side and excavation side, respectively. For the case of no flooding and when the ratio of the distance from the recharge boundary to the aquifer thickness (a/T) is?≥2, the error does not exceed 15%.  相似文献   

9.
Both abiotic and biotic factors govern distributions of estuarine vegetation, and experiments can reveal effects of these drivers under current and future conditions. In upper San Francisco Estuary (SFE), increased salinity could result from sea level rise, levee failure, or water management. We used mesocosms to test salinity effects on, as well as competition between, the native Stuckenia pectinata (sago pondweed) and invasive Egeria densa (Brazilian waterweed), species with overlapping distributions at the freshwater transition in SFE. Grown alone at a salinity of 5, E. densa decreased fivefold in biomass relative to the freshwater treatment and decomposed within 3 weeks at higher salinities. In contrast, S. pectinata biomass accumulated greatly (~4× initial) at salinities of 0 and 5, doubled at 10, and was unchanged at 15. When grown together in freshwater, S. pectinata produced 75 % less biomass than in monoculture and significantly more nodal roots (suggesting increased nutrient foraging). At a salinity of 5, a decline in E. densa performance coincided with a doubling of S. pectinata shoot density. Additional experiments on E. densa showed elevated temperature (26 and 30 °C) suppressed growth especially at higher salinities (≥5). We conclude that salinity strongly influences distributions of both species and that competition from E. densa may impose limits on S. pectinata abundance in the fresher reaches of SFE. With a salinity increase of 5, S. pectinata is likely to maintain its current distribution while spreading up-estuary at the expense of E. densa, especially if increased temperature also reduces E. densa biomass.  相似文献   

10.
The main objective of this study was to investigate the efficiency of biological treatment of azo dye-containing wastewater with a sequencing batch reactor system, followed by ultrafiltration. The performance of the system was quantified by measuring the chemical oxygen demand and azo dye concentration. The biodegradation was carried out under combined alternating anaerobic and aerobic conditions with Nylosan Yellow E2RL SGR as a model azo dye contaminant. The bioprocess revealed a maximal reduction in chemical oxygen demand and dye removal efficiency of 91 and 85%, respectively. After ultrafiltration of effluent from the biological treatment, the efficiency increased to 94% for chemical oxygen demand and to 97% for the azo dye decolourisation. Samples of activated sludge from the bioprocess were collected for microbial characterisation. Bacteria and fungi were isolated and identified by 16S rRNA gene and ITS1-5.8S rDNA-ITS2 sequence analysis, respectively. Serratia marcescens and Klebsiella oxytoca were the most common bacteria with the highest number present during the aerobic and anaerobic phases of the bioprocess. In addition, a high number of Elizabethkingia miricola, Morganella morganii, Comamonas testosteroni, Trichosporon sp. and Galactomyces sp. were detected. Taken together, our results demonstrated that the sequencing batch reactor system combined with ultrafiltration is an efficient technique for treatment of wastewater containing azo dye. Moreover, the ultrafiltration effectively removes the microbiota from the final effluent resulting in stable product water.  相似文献   

11.
By using the lower bound finite elements limit analysis, the pullout capacity of an inclined strip anchor plate embedded in a cohesionless soil medium has been computed with an inclusion of pseudo-static horizontal earthquake body forces. The variation of the pullout capacity factor (F γ ) with changes in horizontal earthquake acceleration co-efficient (α h ) has been computed by varying the inclination angle (β) of the anchor plate between 0° and 90°. The results clearly reveal that the pullout capacity factor (F γ ) decreases significantly with an increase in the value of α h . The reduction in the pullout resistance due to seismic forces (1) becomes much more extensive for a vertical anchor plate as compared to the horizontal anchor, (2) decreases generally with increases in the soil friction angle (?) and (3) increases with an increase in friction angle between soil and anchor plate (δ). The developments of the failure zone around the anchor plate were also examined by varying α h and β. The results obtained from the analysis compare well with the solutions reported in literature.  相似文献   

12.
This paper examines the influence of porous media deformation on water-table wave dispersion in an unconfined aquifer using a numerical model which couples Richards’ equation to the poro-elastic model. The study was motivated by the findings of Shoushtari et al. (J Hydrol 533:412–440, 2016) who were unable to reproduce the observed wave dispersion in their sand flume data with either numerical Richards’ equation models (assuming rigid porous media) or existing analytic solutions. The water-table wave dispersion is quantified via the complex wave number extracted from the predicted amplitude and phase profiles. A sensitivity analysis was performed to establish the influence of the main parameters in the poro-elastic model, namely Young’s modulus (E) and Poisson’s ratio (ν). For a short oscillation period (T?=?16.4 s), the phase lag increase rate (k i) is sensitive to the chosen values of E and ν, demonstrating an inverse relationship with both parameters. Changes in the amplitude decay rate (k r), however, were negligible. For a longer oscillation period (T?=?908.6 s), variations in the values of E and ν resulted in only small changes in both k r and k i. In both the short and long period cases, the poro-elastic model is unable to reproduce the observed wave dispersion in the existing laboratory data. Hence porous media deformation cannot explain the additional energy dissipation in the laboratory data. Shoushtari SMH, Cartwright N, Perrochet P, Nielsen P (2016) The effects of oscillation period on groundwater wave dispersion in a sandy unconfined aquifer: sand flume experiments and modelling. J Hydrol 533:412–440.  相似文献   

13.
The aim of this study was to evaluate the biosorption capacity of selected strains of microscopic fungi. We optimized the biosorption process and used the Freundlich isotherm for three strains: H. haematococca BwIII43, K37 and T. harzianum BsIII33 to describe the biosorption equilibrium of anthraquinone dye, Alizarin Blue Black B (ABBB) and alkali lignin (AL). In optimal conditions (1 g of mycelium biomass, pH = 7.0, 28 °C) for ABBB and AL sorption, the live biomass of H. haematococca BwIII43 was characterized by a higher sorption capacity, amounting to 247.47 and 161.00 mg g?1, respectively. The highest sorption properties toward anthraquinone dye (K F = 19.96 mg g?1) were shown for the biomass of H. haematococca K37. In the presence of alkali lignin, the highest sorption capacity and bond strength exhibited the biomass of H. haematococca BwIII43 (K F = 28.20 mg g?1, n = 3.46). Effective decolorization of ABBB and AL by the selected strains of microscopic fungi indicated that the biosorption process additionally enhanced the removal of color compounds from the solution.  相似文献   

14.
It is shown that the approximation of the complex, tidally distorted shape of a star as a circular disc with local line profiles and a linear limb-darkening law, which is usually applied when deriving equatorial stellar rotation velocities from line profiles, leads to overestimation of the equatorial velocity V rot sin i and underestimation of the component mass ratio q = M x /M v . A formula enabling correction of the effect of these simplifying assumptions on the shape of a star is used to re-determine the mass ratios q and the masses of the black holes M x and visual components M v in low-mass X-ray binary systems containing black holes. Taking into account the tidal–rotational distortion of the stellar shape can significantly increase the mass ratios q = M x /M v , reducing M v , while M x changes only slightly. The resulting distribution of M v attains its maximum near M v ? 0.35M ⊙, in disagreement with the results of population synthesis computations realizing standard models for Galactic X-ray novae with black holes. Possible ways to overcome this inconsistency are discussed. The derived distribution of M x also differs strongly from the mass distribution for massive stars in the Galaxy.  相似文献   

15.
AIA/SDO data in the 193 Å channel preceding a coronal mass ejection observed at the solar limb on June 13, 2010 are used to simultaneously identify and examine two different shock fronts. The angular size of each front relative to the CME center was about 20°, and their propagation directions differed by ≈25° (≈4° in position angle). The faster front, called the blast shock, advanced the other front, called the piston shock, by R ≈ (0.02-0.03)R⊙ (R⊙ is the solar radius) and had a maximum initial speed of VB ≈ 850 km/s (with VP ≈ 700 km/s for the piston shock). The appearance and motion of these shocks were accompanied by a Type II radio burst observed at the fundamental frequency F and second harmonic H. Each frequency was split into two close frequencies f1 and f2 separated by Δf = f2 - f1 ? F, H. It is concluded that the observed frequency splitting Δf of the F and H components of the Type II burst could result from the simultaneous propagation of piston and blast shocks moving with different speeds in somewhat different directions displaying different coronal-plasma densities.  相似文献   

16.
Rapid increases in the amounts of fullerene C60 nanoparticles (nC60) being produced and used will inevitably lead to increases in the amounts released into the aquatic environment. This will have implications for human and ecosystem health. Wastewater treatment plants are key barriers to nC60 being released into aquatic systems, but little information is available on how adsorption processes in wastewater treatment plants affect the fates of nC60. We investigated the effects of the surface properties of activated sludge on the adsorption of nC60 and related mechanisms by modeling the adsorption kinetics and equilibrium process and performing correlation analyses. The adsorption of nC60 closely followed the pseudo-second-order kinetic model (R > 0.983), the Freundlich isotherm model (R > 0.990), and the linear partitioning isotherm model (R > 0.966). Different adsorption coefficients, 1.070–4.623 for the Freundlich partitioning model and 1.788–6.148 for the linear partitioning model, were found for different types of activated sludge. The adsorption coefficients significantly positively correlated with the zeta (ζ) potential (R = 0.877) and hydrophobicity (R = 0.661) and negatively correlated with particle size (R = ?0.750). The results show that nC60 adsorption is strongly affected by the surface properties of activated sludge because changes in surface properties cause changes in the electrostatic and hydrophobic interactions that occur.  相似文献   

17.
We have modeled the magnetic fields of the slowly rotating stars HD 116458 and HD 126515 using the “magnetic charge” technique. HD 116458 has a small angle between its rotation axis and dipole axis (β = 12°), whereas this angle is large for HD 126515 (β = 86°). Both stars can be described with a decentered-dipole model, with the respective displacements being r = 0.07 and r = 0.24 in units of the stellar radius. The decentered-dipole model is able to satisfactorily explain the phase relations for the effective field, Be(P), and the mean surface field, Bs(P), for both stars, along with the fact that the Be(P) phase relation for HD 126515 is anharmonic. We discuss the role of systematic measurement errors possibly resulting from instrumental or methodical effects in one or both of the phase relations. The displacement of the dipole probably reflects real asymmetry of the stellar field structure, and is not due to measurement errors. Using both phase relations, Be(P) and Bs(P), in the modeling considerably reduces the influence of the nonuniform distribution of chemical elements on the stellar surface.  相似文献   

18.
This paper investigates, using the random field theory and Monte Carlo simulation, the effects of random field discretization on failure probability, p f, and failure mechanism of cohesive soil slope stability. The spatial sizes of the discretized elements in random field Δx, Δy in horizontal and vertical directions, respectively, are assigned a series of combinational values in order to model the discretization accuracy. The p f of deterministic critical slip surface (DCSS) and that of the slope system both are analyzed. The numerical simulation results have demonstrated that both the ratios of Δy/λ y (λ y  = scale of fluctuation in vertical direction) and Δx/λ x (λ x  = scale of fluctuation in horizontal direction) contribute in a similar manner to the accuracy of p f of DCSS. The effect of random field discretization on the p f can be negligible if both the ratios of Δx/λ x and Δy/λ y are no greater than 0.1. The normalized discrepancy tends to increase at a linear rate with Δy/λ y when Δx/λ x is larger than 0.1, and vice versa for p f of DCSS. The random field discretization tends to have more considerable influence on the p f of DCSS than on that of the slope system. The variation of p f versus λ x and λ y may exhibit opposite trends for the cases where the limit state functions of slope failure are defined on DCSS and on the slope system as well. Finally, the p f of slope system converges in a more rapid manner to that of DCSS than the failure mechanism does to DCSS as the spatial variability of soil property grows from significant to negligible.  相似文献   

19.
The lipA gene, encoding a solvent-tolerant extracellular lipase from Proteus sp. SW1, was displayed on the cell surface of Escherichia coli by fusing it to an antigen 43 anchoring motif. The display of LipA on the Escherichia coli cell surface was directly confirmed by immunofluorescence microscopy and flow cytometry. After 6 days of incubation in media containing 1 % used cooking oil, an Escherichia coli strain expressing surface displayed lipase was able to degrade 27 % of the oil. The biosurfactant, pseudopyronine B, was purified from culture supernatants of Pseudomonas sp. SL31. Its critical micelle concentration was determined to be 1400 mg/l, and the surfactant was stable within a temperature range from 0 to 120 °C and a pH range of 3–11. Pseudopyronine B-containing crude media extracts efficiently removed up to 51 % of the cadmium from contaminated water. We demonstrated the oil degradation ability of the mixed culture of four bacterial strains, namely the recombinant Escherichia coli expressing cell surface displayed lipase (pKKJlipA), His-tagged lipase (pETlipA), extracellular lipase-producing Proteus sp. SW1, and pseudopyronine B-producing Pseudomonas sp. SL31 by culturing in LB media containing 1 % oil. The consortium degraded 29 % of oil in one day and reached 84 % after 7 days.  相似文献   

20.
The rock mass failure process can be divided into several distinct deformation stages: the compaction stage, elastic stage, stable failure stage, accelerated failure stage, and post-peak stage. Although each stage has been well studied, the relationship among the stages has not been established. Here, we establish two models which are the Strain model Q and Energy density model S by using the renormalization group theory and investigate the mechanical relationship between the volume dilatant point and peak stress point on the rock stress-strain curve. Our models show that the strain ratio (ε f /ε c ) and energy ratio (E f /E c ) at the volume dilatant point and peak stress point are solely functions of the shape parameter m. To verify our models, we further studied the failure process of rock specimens through several uniaxial compression experiments and found that the relationship between ε f /ε c or E f /E c and m shares a notably similar pattern to that from our theoretical model. However, the ε f /ε c and E f /E c values in our experiments are slightly smaller than those predicted by the models. In brief, we demonstrate that our models can be used to predict the failure process of the laboratory-scale hard brittle rock samples.  相似文献   

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