960 research outputs found
Global and blow-up solutions for quasilinear parabolic equations with a gradient term and nonlinear boundary flux
Modeling and Simulation for Steady State and Transient Pipe Flow of Condensate Gas
Condensate gas is mainly demonstrated by methane. However, it also contains a lot of heavier contents like C5 or C5+ and some non-hydrocarbon mixture as well (Mokhatab et al, 2006). After recovering from gas wells, condensate gas needs liquid separation, gas purification and condensate stabilization treatment in the processing plant to meet the quality requirements. Processing plants far away from the gas well with long distances of two-phase flow in one condensate gas pipeline will take less investment than adjacent process plant with two single phase pipelines which are dry gas pipeline and liquid phase pipeline (Li, 2008). If the operation temperature somewhere in the condensate gas pipeline is lower than the gas dew point, liquid condensation would occur, subjecting the pipeline to two phase flow (Potocnik, 2010). While gas and its condensate flow simultaneously, mass transfer takes place continuously due to the change in pressure and temperature conditions. This leads to compositional changes and associated fluid property changes and also makes the hydraulic and thermal calculations of condensate gas more complex than normal gas. The condensate gas pipeline model which is established and solved based on the principle of fluid mechanics can simulate hydraulic and thermal parameters under various operation conditions. By means of technical support, this model is of great importance in the pipeline design and safety operation aspects (Mokhatab, 2009)
Novel Cyanine-AMP Conjugates for Efficient 5\u27 RNA Fluorescent Labeling by One-Step Transcription and Replacement of [γ-\u3csup\u3e32\u3c/sup\u3eP] ATP in RNA Structural Investigation
Two novel fluorescent cyanine-AMP conjugates, F550/570 and F650/670, have been synthesized to serve as transcription initiators under the T7 φ2.5 promoter. Efficient fluorophore labeling of 5′ RNA is achieved in a single transcription step by including F550/570 and F650/670 in the transcription solution. The current work makes fluorescently labeled RNA readily available for broad applications in biochemistry, molecular biology, structural biology and biomedicine. In particular, site-specifically fluorophore-labeled large RNAs prepared by the current method may be used to investigate RNA structure, folding and mechanism by various fluorescence techniques. In addition, F550/570 and F650/670 may replace [γ-32P]ATP to prepare 5′ labeled RNA for RNA structural and functional investigation, thereby eliminating the need for the unstable and radio-hazardous [γ-32P]ATP
Optimal Energy Consumption Analysis of Natural Gas Pipeline
There are many compressor stations along long-distance natural gas pipelines. Natural gas can be transported using different boot programs and import pressures, combined with temperature control parameters. Moreover, different transport methods have correspondingly different energy consumptions. At present, the operating parameters of many pipelines are determined empirically by dispatchers, resulting in high energy consumption. This practice does not abide by energy reduction policies. Therefore, based on a full understanding of the actual needs of pipeline companies, we introduce production unit consumption indicators to establish an objective function for achieving the goal of lowering energy consumption. By using a dynamic programming method for solving the model and preparing calculation software, we can ensure that the solution process is quick and efficient. Using established optimization methods, we analyzed the energy savings for the XQ gas pipeline. By optimizing the boot program, the import station pressure, and the temperature parameters, we achieved the optimal energy consumption. By comparison with the measured energy consumption, the pipeline now has the potential to reduce energy consumption by 11 to 16 percent
The Impacts of Shanghai’s July 2019 Municipal Domestic Waste Management Regulations on Energy Production
Cities all over the world are trying to divert municipal waste away from landfill and fossil fuel-assisted incineration and toward circular economies where waste is converted into new resources. Residential food waste is the most challenging sub-stream, as it is the worst culprit in producing greenhouse gases in landfill and incineration, and it is almost impossible to have residents separate it cleanly at source. Here we investigate the outstanding diversion results of Shanghai Municipality since the introduction of the July 2019 Municipal Regulations, of over 9600 tons per day of clean food waste, still maintained two years later. In particular, we question why they might have increased so sharply after July 2019 and examine historic policies to determine broad policy intentions, their implementations, and officially reported tonnages of different resulting waste streams. It was found that many prior steps included infrastructure building and piloting different behavioral approaches. However, the July 2019 policy brought in legal responsibilities to very clearly defined roles for each stakeholder—including for the residents to sort and for local governances to support them—and this pulled all the operational elements together. The immediate and sustained jumps in clean food waste collection fed biogas production (0.1–1.0 GWh/day) and energy-from-waste (less wet) (5.4–8.6 GWh/day)
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