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1.
Upflow anaerobic sludge blanket (UASB) methane fermentation treatment of cow manure that was subjected to screw pressing, thermal treatment and subsequent solid-liquid separation was studied. Conducting batch scale tests at temperatures between 140 and 180 degrees C, the optimal temperature for sludge settling and the color suppression was found to be between 160-170 degrees C. UASB treatment was carried out with a supernatant obtained from the thermal treatment at the optimal conditions (170 degrees C for 30 minutes) and polymer-dosed solid-liquid separation. In the UASB treatment with a COD(Cr) loading of 11.7 kg/m3/d and water temperature of 32.2 degrees C, the COD(Cr) level dropped from 16,360 mg/L in raw water to 3,940 mg/L in treated water (COD(Cr), removal rate of 75.9%), and the methane production rate per COD(Cr) was 0.187 Nm3/kg. Using wastewater thermal-treated at the optimal conditions, also a methane fermentation treatment with a continuously stirred tank reactor (CSTR) was conducted (COD(Cr) in raw water: 38,000 mg/L, hydraulic retention time (HRT): 20 days, 35 degrees C). At the COD(Cr) loading of 1.9 kg/m3/d, the methane production rate per COD(Cr), was 0.153 Nm3/kg. This result shows that UASB treatment using thermal pre-treatment provides a COD(Cr), loading of four times or more and a methane production rate of 1.3 times higher than the CSTR treatment. 相似文献
2.
In this paper, implementation of the Benchmark Simulation Model No 2 (BSM2) within Matlab-Simulink is presented. The BSM2 is developed for plant-wide WWTP control strategy evaluation on a long-term basis. It consists of a pre-treatment process, an activated sludge process and sludge treatment processes. Extended evaluation criteria are proposed for plant-wide control strategy assessment. Default open-loop and closed-loop strategies are also proposed to be used as references with which to compare other control strategies. Simulations indicate that the BM2 is an appropriate tool for plant-wide control strategy evaluation. 相似文献
3.
A. A. Salem S. R. Kalidindi R. D. Doherty S. L. Semiatin 《Metallurgical and Materials Transactions A》2006,37(1):259-268
Novel experiments were conducted to elucidate the effect of deformation twinning on the mechanical response of high-purity
α-titanium deformed at room temperature. Orientation-imaging microscopy (OIM), microhardness, and nanohardness evaluations
were employed in conjunction with optical microscopy and quasi-static compression testing to obtain insight into the deformation
mechanisms. Hardness measurements revealed that the newly formed deformation twins were harder than the matrix. This observation
is perhaps the first experimental evidence for the Basinski mechanism for hardening associated with twinning, arising from
the transition of glissile dislocations to a sessile configuration upon the lattice reorientation by twinning shear. This
work also provided direct evidence for two competing effects of deformation twinning on the overall stress-strain response:
(1) hardening via both a reduction of the effective slip length (Hall-Petch effect) and an increase in the hardness of twinned regions (Basinski
mechanism) and (2) softening due to the lattice reorientation of the twinned regions. 相似文献
4.
5.
Martins Silvia S.; Mazzotti Guido; Chilcoat Howard D. 《Canadian Metallurgical Quarterly》2006,14(3):275
Background: Despite increases in ecstasy (MDMA) use in the United States, little is known about characteristics linked with recent-onset ecstasy use, especially psychiatric symptoms and deviant behaviors. Aims: To test whether individuals with high levels of other drug use are more likely to be recent-onset ecstasy users; to test whether psychiatric symptoms in adults are associated with recent-onset ecstasy use; to explore the association between recent-onset ecstasy use and concomitant deviant behaviors in adolescents and adults. Methods: Data from the 2001 National Survey on Drug Use and Health. Findings: Recent-onset ecstasy use was significantly more likely to occur among adolescents and adults (18-34 years old) who engaged in deviant behaviors during the past year as compared with those who did not engage in deviant behaviors during the past year. Higher levels of deviancy indicated a higher likelihood of being a recent-onset ecstasy user, and associations were strongest with nonviolent deviant behaviors such as selling illegal drugs and stealing. Associations between deviant behaviors and recent-onset ecstasy use were similar in strength to associations between deviant behaviors and recent-onset cocaine and marijuana use, respectively. Adults who had past-year psychiatric symptoms (both depressive and panic symptoms) were twice as likely to be recent-onset ecstasy users as compared with those without past-year psychiatric symptoms. Greater levels of drug involvement increased the odds of being a recent-onset ecstasy user. Conclusion: Recent-onset ecstasy use seems to be associated with a range of other behavioral problems and may reflect one aspect of a larger problem behavior syndrome. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
D. A. Mirzaev N. I. Vorob’ev O. K. Tokovi D. V. Shaburov E. A. Fominykh 《Russian Metallurgy (Metally)》2006,(1):38-41
The solutions to a differential equation for the problem of heating of a cylinder in a medium with a fixed temperature are used to obtain equations for estimating the change in the hydrogen concentration in forgings from data on the hydrogen concentration at the cylinder axis or on the average bulk hydrogen concentration. Similar equations are also obtained for forgings having square cross sections. The calculation demonstrates that, for the case of a twofold decrease in the hydrogen concentration in a forging, the calculated times of annealing of a cylindrical forging differ by three times. 相似文献
7.
P. B. Lovyrev A. I. Lavrov V. A. Babkin A. N. Aminov S. M. Melekhin Yu. P. Kazantsev P. M. Korol’kov 《Metallurgist》2006,50(3-4):152-157
Specifications require that all the welds in 12-m-diam. decomposers with a capacity of 3600 m3 be subjected to high-temperature tempering before going into service in order to alleviate the stresses from the welding
operation. Specialists at the organizations VNIIPTkhimnefteapparatury and VNIImontazhspetsstroi have proposed out-of-furnace
volumetric (complete) of the assembled decomposer with the use of special heaters. The use of this heating method has shortened
assembly operations while providing the welds with a highquality heat treatment and reducing the stresses overall (including
welding stresses, stresses from assembly of the decomposer, etc.) The technology ensures uniform heating of the housing of
the decomposer and provides for close control over the process. The experience gained in heat-treating decomposers can also
be used in the construction of other containers that come into contact with corrosive media.
__________
Translated from Metallurg, No. 3, pp. 61–64, March, 2006. 相似文献
8.
In this study, feasibility of membrane separation for the removal of indigenous noroviruses (NVs) is evaluated. The indigenous NV gene was never detected from ultrafiltration (UF) permeates of sewage sludge and treated wastewater. Indigenous NV gene was also not detected from permeates of sewage sludge and treated wastewater by microfiltration (MF) with a pore size of 0.1 microm (MF0.1). Even though the pore size of MF (0.1 microm) was much larger than the diameter of virus particle (approximately 30-40nm), more than 4-log10 reduction value (LRV) at maximum was achieved by membrane separation with MF0.1. NV genes were often detected from permeates of sewage sludge and treated wastewater by MF with a pore size of 0.45 microm (MF0.45), although the maximum log10 reduction values were more than 3.59 for sewage sludge and more than 2.90 for treated wastewater. It is important to verify factors determining the removal efficiency of viruses with MF membranes. 相似文献
9.
Beneficial effects of wettability altering surfactants in oil-wet fractured reservoirs 总被引:3,自引:0,他引:3
Subhash C. Ayirala Chandra S. Vijapurapu Dandina N. Rao 《Journal of Petroleum Science and Engineering》2006,52(1-4):261
In fractured reservoirs, an effective matrix-fracture mass transfer is required for oil recovery. Surfactants have long been considered for oil recovery enhancement, mainly in terms of their ability to reduce oil–water interfacial tension. These surfactants are effective when the fractured formations are water-wet, where capillary imbibition of surfactants from the fracture into the matrix contributes to oil recovery. However, another beneficial aspect of surfactants, namely their ability to alter wettability, remains to be explored and exploited. Surfactants capable of altering wettability can be especially beneficial in oil-wet fractured formations, where the surfactant in the fracture diffuses into the matrix and alters the wettability, enabling imbibition of even more surfactant into the matrix. This sequential process of initial diffusion followed by imbibition continues well into the matrix yielding significant enhancements in oil recovery.In order to test this hypothesis of sequential diffusion–imbibition phenomenon, Dual-Drop Dual-Crystal (DDDC) contact angle experiments have been conducted using fractured Yates dolomite reservoir fluids, two types of surfactants (nonionic and anionic) and dolomite rock substrates. A new experimental procedure was developed in which crude oil equilibrated with reservoir brine has been exposed to surfactant to simulate the matrix-fracture interactions in fractured reservoirs. This procedure enables the measurements of dynamic contact angles and oil–water interfacial tensions, in addition to providing the visual observations of the dynamic behavior of crude oil trapped in the rock matrix as it encounters the diffusing surfactant from the fractures. Both the measurements and visual observations indicate wettability alterations of the matrix surface from oil-wet to less oil-wet or intermediate wet by the surfactants. Thus this study is of practical importance to oil-wet fractured formations where surfactant-induced wettability alterations can result in significant oil recovery enhancements. In addition, this study has also identified the need to include contact angle term in the dimensionless Bond number formulations for better quantitative interpretation of rock–fluids interactions. 相似文献
10.
N. I. Nikolaikin E. Yu. Barzilovich N. E. Nikolaikina 《Chemical and Petroleum Engineering》2006,42(5-6):332-338
The paper discusses optimal control of ecosystem state for observation of a generalized monotonically varying random parameter.
A model is proposed for the controlled vector random process, whose components are assigned acceptable ranges and the observations
are performed discretely.
__________
Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, No. 6, pp. 40–44, June, 2006. 相似文献