421 research outputs found
Improving Short-Term Electricity Price Forecasting Using Day-Ahead LMP with ARIMA Models
Short-term electricity price forecasting has become important for demand side
management and power generation scheduling. Especially as the electricity
market becomes more competitive, a more accurate price prediction than the
day-ahead locational marginal price (DALMP) published by the independent system
operator (ISO) will benefit participants in the market by increasing profit or
improving load demand scheduling. Hence, the main idea of this paper is to use
autoregressive integrated moving average (ARIMA) models to obtain a better LMP
prediction than the DALMP by utilizing the published DALMP, historical
real-time LMP (RTLMP) and other useful information. First, a set of seasonal
ARIMA (SARIMA) models utilizing the DALMP and historical RTLMP are developed
and compared with autoregressive moving average (ARMA) models that use the
differences between DALMP and RTLMP on their forecasting capability. A
generalized autoregressive conditional heteroskedasticity (GARCH) model is
implemented to further improve the forecasting by accounting for the price
volatility. The models are trained and evaluated using real market data in the
Midcontinent Independent System Operator (MISO) region. The evaluation results
indicate that the ARMAX-GARCH model, where an exogenous time series indicates
weekend days, improves the short-term electricity price prediction accuracy and
outperforms the other proposed ARIMA modelsComment: IEEE PES 2017 General Meeting, Chicago, I
Kinetic enhancement of adsorbent for CO2 capture from atmosphere by porous material
Strategies for stabilizing atmospheric greenhouse gas concentrations will need to consider future CO2 emissions from an enormous resource of worldwide fossil fuel supplies and a diverse range of mitigation technologies. In 2013, global CO2 emissions due to fossil fuel use (and cement production) were 36 gigatonnes (Gt CO2), and are projected to increase by an additional 2.5% in 2014. Even if all emissions from large fixed sources could be captured, the roughly 30-50% of global emissions due to transportation and mobile sources would still be released into the atmosphere. To ensure the concentration of atmospheric CO2 in the scope of security, CO2 air capture, which offers the potential to be a truly carbon negative technology, is urgent.
The design and preparation of porous materials with controlled structures and functionalities is crucial to low concentration CO2 capture. In this work, two preparation approaches of CO2 adsorbents are explored. One is heterogeneous membrane preparation using porous supporting materials through phase inversion method, which is relatively simple, rapid, and inexpensive, and the other is to directly prepare the porous adsorbents through grafting method using a novel material—cellulose. For phase inversion method, anion exchange resin, which can absorb low concentration CO2 after ion exchange treatment, is mixed with Polyethersulfone (PES), N-Methyl pyrrolidone (NMP) and Macrogol 400(PEG-400) to form casting solution, and finally, the heterogeneous membrane is prepared for CO2 adsorption. For grafting method, the cellulos anion exchange fiber used for CO2 adsorption, is prepared by alkali pretreatment of sodium hydroxide and the grafting of epichlorohydrin and ethylenediamine onto fiber, and finally ion exchange treatment is made to introduce basic groups, such as carbonate ions and hydroxide ion. The surface properties of the prepared adsorption materials are characterized by SEM and BET, as can be seen in Figure 1, and the results reveal that the materials are porous and have large specific surface area, which is beneficial to the kinetics of CO2 adsorption. The absorption performances of the two kinds of adsorbents are tested on a self-made rotating bed reactor, and the absorption capacity and kinetics are compared. To optimize the kinetics performance of CO2 adsorption, the modified shrinking core model (SCM) is used to analyze the resistance during the reaction process according to the test results. The resistance during the mass transfer process includes physical diffusion resistance and chemical reaction resistance. For the heterogeneous membrane, the results reveal that the resistance of physical diffusion and chemical reaction is comparable when the saturation of CO2 adsorption is low (less than 0.3), and the physical diffusion resistance increases greatly and controls the kinetics performance when the saturation of CO2 is high, as can be seen in Figure 2. The influence of temperature and humidity on CO2 adsorption kinetics is also studied and the diffusion coefficient and reaction rate constant are obtained, and the activation energy of reaction can be determined
Sustainable Food and Fuel on Yongxing Island by Conversing the Carbon Captured from Ambient Air
AbstractSynthetic hydrocarbon fuel, derived from renewable energy and captured carbon dioxide from ambient air, can thoroughly close its carbon cycle and is a promising option for CCU and an important approach to sustainable energy. We investigate the Yongxing island in south China sea, which offers steady wind resources to provide continuous energy supply for plant factory and fuel synthesis. The energy consumption of MSAC and TSAC is compared and conversion of the captured CO2 to food and fuel are calculated. Powered by wind energy, 200 ton vegetables and 5.2*103 ton diesel will be produced per year, so self-sufficiency of vegetable and fuel demand can be achieved on Yongxing island. Our methodology could provide a new utilization mode for islands like Yongxing island
Egg white-mediated green synthesis of silver nanoparticles with excellent biocompatibility and enhanced radiation effects on cancer cells
A simple, cost-effective, and environmentally friendly approach to the aqueous-phase synthesis of silver (Ag) nanoparticles was demonstrated using silver nitrate (AgNO3) and freshly extracted egg white. The bio-conjugates were characterized by UV-visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectrometry, and dynamic light scattering. These results indicated that biomolecule-coated Ag nanoparticles are predominantly spherical in shape with an average size of 20 nm. The proteins of egg white, which have different functional groups, played important roles in reducing Ag+ and maintaining product attributes such as stability and dispersity. In vitro cytotoxicity assays showed that these Ag-protein bio-conjugates showed good biocompatibility with mouse fibroblast cell lines 3T3. Furthermore, X-ray irradiation tests on 231 tumor cells suggested that the biocompatible Ag-protein bio-conjugates enhanced the efficacy of irradiation, and thus may be promising candidates for use during cancer radiation therapy
Gas-Solids Hydrodynamics in a CFB with 6 Cyclones and a Pang Leg
Solids volume fraction and particle velocity profiles were measured with a fiber optical probe in a cold circulating fluidized bed test rig with 6 parallel cyclones and a pant leg. Results in the pant leg zone, main bed zone and exit zone of the furnace are reported. The work also includes the influences of superficial gas velocity, secondary air rate and static bed height on the gas-solids hydrodynamics
Drug Target Prediction Based on the Herbs Components: The Study on the Multitargets Pharmacological Mechanism of Qishenkeli Acting on the Coronary Heart Disease
In this paper, we present a case study of Qishenkeli (QSKL) to research TCM's underlying molecular mechanism, based on drug target prediction and analyses of TCM chemical components and following experimental validation. First, after determining the compositive compounds of QSKL, we use drugCIPHER-CS to predict their potential drug targets. These potential targets are significantly enriched with known cardiovascular disease-related drug targets. Then we find these potential drug targets are significantly enriched in the biological processes of neuroactive ligand-receptor interaction, aminoacyl-tRNA biosynthesis, calcium signaling pathway, glycine, serine and threonine metabolism, and renin-angiotensin system (RAAS), and so on. Then, animal model of coronary heart disease (CHD) induced by left anterior descending coronary artery ligation is applied to validate predicted pathway. RAAS pathway is selected as an example, and the results show that QSKL has effect on both rennin and angiotensin II receptor (AT1R), which eventually down regulates the angiotensin II (AngII). Bioinformatics combing with experiment verification can provide a credible and objective method to understand the complicated multitargets mechanism for Chinese herbal formula
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