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991.
992.
Polyaspartate is an excellent Pb2+‐binding agent in comparison with some polyaspartamide derivatives with different side chains, in that it possesses a higher Pb2+ uptake and a lower Pb2+ equilibrium concentration. Equilibrium sorption data for Pb2+ on polyaspartate can be well fitted with the Freundlich and Langmuir models. Experimental results show that a crosslinked polyaspartate hydrogel is superior to poly(acrylic acid)‐based resins and polystyrene‐based chelating resins. IR spectra and X‐ray photoelectron spectra reveal that the polyaspartate hydrogel binds Pb2+ by both an ion‐exchange mechanism and a chelating mechanism. The polyaspartate hydrogel is also an effective agent for the removal of Pb2+ from glycyrrhizin. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2215–2220, 2005 相似文献
993.
994.
Extraction of Lipids from Municipal Wastewater Plant Microorganisms for Production of Biodiesel 总被引:2,自引:0,他引:2
Stephen Dufreche R. Hernandez T. French D. Sparks M. Zappi E. Alley 《Journal of the American Oil Chemists' Society》2007,84(2):181-187
Municipal wastewater treatment plants in the USA produce over 6.2 × 106 t of dried sewage sludge every year. This microorganism-rich sludge is often landfilled or used as fertilizer. Recent restrictions
on the use of sewage sludge, however, have resulted in increased disposal problems. Extraction of lipids from sludge yields
an untapped source of cheap feedstock for biodiesel production. Solvents used for extraction in this study include n-hexane, methanol, acetone, and supercritical CO2. The gravimetric yield of oil was low for nonpolar solvents, but use of polar solvents gave a considerably increased yield;
however, the percentage of saponifiable material was less. Extraction of lipids with a mixture of n-hexane, methanol, and acetone gave the largest conversion to biodiesel compared with other solvent systems, 4.41% based on
total dry weight of sludge. In situ transesterification of dried sludge resulted in a yield of 6.23%. If a 10% dry weight
yield of fatty acid methyl esters is assumed, the amount of biodiesel available for production in the USA is 1.4 × 106 m3/year. Outfitting 50% of municipal wastewater plants for lipid extraction and transesterification could result in enough biodiesel
production to replace 0.5% of the national petroleum diesel demand (0.7 × 106 m3). 相似文献
995.
新型干法生产技术的核心即预分解技术在我国的水泥生产中已越来越多地被采用。随着国家对“四小”企业政策的出台,由原立窑企业投资建设的新型干法生产线越来越多,但一些厂家并未适用新型干法生产的特殊要求,仍旧延续原立窑厂特有的一套管理方法,造成资源上一些不必要的浪费,生 相似文献
996.
997.
Kinetic study of Chinese biomass slow pyrolysis: Comparison of different kinetic models 总被引:7,自引:0,他引:7
The slow pyrolysis of six Chinese biomasses was studied by thermogravimetric experiments. Non-linear square fitting method is used to calculate DTG data. The analysis results show that it is not possible to exactly represent the biomass pyrolysis by a one-step model with different mechanisms. Thus, three-pseudocomponent models were used to simulate the biomass pyrolysis. It was found that the three-pseudocomponent model with n-order kinetics (model II) is more accurate than the model with first-order kinetics (model I). Activation energies of three-pseudocomponents in model II are bigger than the values in model I. It is shown that model II yields the best simulation results, especially with respect to describe accurately the pyrolysis of the first pseudocomponent (hemicellulose) and the last one (lignin). Nevertheless, with regard to a practical utilization, the three-pseudocomponent model with a reaction order of one could be used, because the accuracy to represent biomass pyrolysis is high enough. Unrealistic high values of the reaction order are avoided, and thus this model is more realistic with respect to the chemical interpretation of the reaction order. 相似文献
998.
The time dependences of electrical conduction and self‐heating behaviors in high‐density polyethylene filled with acetylene carbon black of 0.082 in volume fraction are studied in relation to voltage and ambient temperature. The characteristic decay current constant τi, and the exponential growth time constant for self‐heating τg are determined for the samples under voltages U above the critical value Uc for the onset of self‐heating. The influences of voltage and ambient temperature on τi and τg as well as the amplitude of the low‐resistance to high‐resistance switching are discussed on the basis of the random resistor network (RRN) model and the relationship between Uc and the intrinsic resistivity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1124–1131, 2006 相似文献
999.
J. Javier Gutiérrez J. Carlos Palencia Michael González Harbour 《Real-Time Systems》2014,50(2):230-269
The ARINC-664, Part 7 (AFDX) standard defines a communication network based on Ethernet and the UDP/IP protocols. Contrary to general-purpose Ethernet, the timing behavior in AFDX is deterministic due to the use of special network switches and end systems with static routing tables and traffic policing at the sending end through mechanisms called virtual links. Even though the latencies in this network are bounded, there are scheduling and contention effects that need to be analyzed. In this paper we develop a response-time analysis for multipacket messages transmitted through an AFDX network including the scheduling of the virtual links and sub-virtual links, and also the contention in the end systems and in the switches. This analysis allows us to obtain worst-case latencies and output jitter for the network messages with a precise modeling of the sending and receiving ends. These results can be integrated in a holistic approach with the response time analysis of the threads in the processing nodes to obtain end-to-end response times in heterogeneous distributed systems. 相似文献
1000.
Qin Zou Yu Cao Qingquan Li Qingzhou Mao Song Wang 《Machine Vision and Applications》2014,25(7):1841-1858
Recent inpainting techniques usually require human interactions which are labor intensive and dependent on the user experiences. In this paper, we introduce an automatic inpainting technique to remove undesired fence-like structures from images. Specifically, the proposed technique works on the RGBD images which have recently become cheaper and easier to obtain using the Microsoft Kinect. The basic idea is to segment and remove the undesired fence-like structures by using both depth and color information, and then adapt an existing inpainting algorithm to fill the holes resulting from the structure removal. We found that it is difficult to achieve a satisfactory segmentation of such structures by only using the depth channel. In this paper, we use the depth information to help identify a set of foreground and background strokes, with which we apply a graph-cut algorithm on the color channels to obtain a more accurate segmentation for inpainting. We demonstrate the effectiveness of the proposed technique by experiments on a set of Kinect images. 相似文献