Transactive energy management for optimal scheduling of interconnected microgrids with hydrogen energy storage

In recent years, renewable energy sources (RESs) have attracted substantial attention due to carbon-free and cost-effective advantages that have made them one of the main sources of energy generation in the modern structure of the power grid. This paper proposes the stochastic day-ahead scheduling model for optimal energy management of renewable-based microgrids. In this paper, each microgrid is equipped with 100% RESs including the PV system and wind turbine for full pollutant-free energy generation while the hydrogen energy storage (HES) system is used for alleviating the intermittences of the RESs aiming to dynamically balance the energy during a day. To model the fluctuations such as day-ahead market price in the microgrids, the autoregressive integrated moving average and fast forward selection methods are exerted for scenario production and reduction, respectively. Transactive energy as a sustainable and reliable technique is considered for controlling and coordinating energy sharing among the microgrids and the energy network for dynamic energy balancing in the deregulated environment. For energy management in the demand-side, the price and load response schemes are presented, aiming to revise the consumers' patterns in energy consumption in line with balancing energy and minimizing the microgrids’ energy cost. The effectiveness of the suggested model is validated using the modified IEEE 24-bus case study. The realistic modeling of the system based on the proposed model has led to an 8.51% increment in energy cost.     

Cutting forces in bandsaw processing of oak and beech wood as affected by wood moisture content and cutting directions

Cutting forces in bandsaw processing of oak and beech wood were measured at two levels of wood moisture content (about 12 % and FSP) for four cutting directions (90°–90°, 90°–0°, 0°–90° and 90°–45°). A constant cutting speed of 40 m/s and a feed rate of 20 m/min were applied. A piezoelectric dynamometer (KISTLER type 9257A) mounted on the carriage of the vertical bandsaw machine (ESTERER model EB 1400) was used to measure the parallel, normal and lateral cutting forces. Results revealed that all cutting forces depend on the wood moisture content and cutting direction. The greatest parallel force was observed for oak wood at 12 % MC for 90°–90° cutting direction (44 N/mm) whereas the lowest one was for beech wood at 30 % MC for 0°–90° cutting direction (20 N/mm). In contrast to the little change of lateral force at various cutting directions, the change in parallel force was significant.     

Synthesis and gas permeation properties of a single layer PDMS membrane

In this work, a new polydimethylsiloxane (PDMS) membrane was synthesized and its sorption, diffusion, and permeation properties were investigated using H₂, N₂, O₂, CH₄, CO₂, and C₃H₈ as a function of pressure at 35°C. PDMS, as a rubbery membrane, was confirmed to be more permeable to more condensable gases such as C₃H₈. The synthesized PDMS membrane showed much better gas permeation performance than others reported in the literature. Based on the sorption data of this study and other researchers' works, some valuable parameters such as Flory‐Huggins (FH) interaction parameters, χ, etc., were calculated and discussed. The concentration‐averaged FH interaction parameters of H₂, N₂, O₂, CH₄, CO₂, and C₃H₈ in the synthesized PDMS membrane were estimated to be 2.196, 0.678, 0.165, 0.139, 0.418, and 0.247, respectively. Chemical similarity of O₂, CH₄, and C₃H₈ with backbone structure of PDMS led to lower χ values or more favorable interactions with polymer matrix, particularly for CH₄. Regular solution theory was applied to verify correctness of evaluated interaction parameters. Local effective diffusion coefficient of C₃H₈ and CO₂ increased with increasing penetrant concentration, which indicated the plasticization effect of these gases over the range of penetrant concentration studied. According to high C₃H₈/gas ideal selectivity values, the synthesized PDMS membrane is recommended as an efficient membrane for the separation of organic vapors from noncondensable gases. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A kinetic study of Pd–Au catalyzed synthesis of vinyl acetate from oxidation of ethylene and acetic acid in heterogeneous gas reaction

While qualitative interpretation of the experimental results is often limited to the identification of global mechanistic phenomena, kinetic modeling is a more powerful tool for the identification of the chemical reaction network that can describe the experimental results. In this paper, kinetic study of vinyl acetate (VA) synthesis was performed in a fixed bed reactor with oxidation of ethylene and acetic acid in gaseous phase over Pd/Au/SiO₂ catalyst under the industrial relevant reaction condition as follows: temperature of 120–165 °C, at constant pressure of 8 bar and the ratio of catalyst mass to the feed (W/F) was maintained at 70 g/mol min. Variation in partial pressure and concentration of reactants have led us to determine the rate limiting step and therefore proposing a new rate low based on Langmuir-Hinshelwood–Hougen–Watson (LHHW) approached consistent with experimental observation while adapted through mathematical formulation with high reliance. So, the kinetic parameters were determined by the Levenberg–Marquardt algorithm. Effect of temperature has also been surveyed showing a decreased in selectivity due to the difference in reaction constants of main and side reaction rate and an increase rate due to the increase in apparent activation energy.     

Experimental and modeling approach to study separation of water in crude oil emulsion under non-uniform electrical field

In many ways, the use of high electrostatic fields in the separation of water-in-oil emulsions is a mature technology, with most developments arising from attempts to improve the process of crude oils, in terms of the separation of water, salt or other hydrophilic impurities. In this way, different mechanisms have been proposed until now and several parameters have been studied to estimate the level of separation. In this work, after a review of the process and its application, new results are presented for AC currents under non-uniform electrical fields (dielectrophoresis) on the water-in-crude oil emulsion. Then the effects of voltage, temperature, volume fraction and API are studied on degree of separation. Finally, a correlation is presented among these parameters by an experimental model.     

Recognizing acronyms and their definitions

This paper introduces an automatic method for finding acronyms and their definitions in free text. The method is based on an inexact pattern matching algorithm applied to text surrounding the possible acronym. Evaluation shows both high recall and precision for a set of documents randomly selected from a larger set of full text documents. Received October 1, 1997 / Revised September 8, 1998     

Ring opening reactions of glycidyl methacrylate copolymers to introduce bulky organosilicon side chain substituents

Summary Glycidyl methacrylate (GMA) random copolymers with methyl acrylate (MA), ethyl acrylate (EA), n-butyl acrylate (BA), methyl methacrylate (MMA), ethyl methacrylate (EMA) and n-butyl methacrylate (BMA) were synthesized by solution free radical polymerizations, at 70±1 °C using α,α’-azobis(isobutyronitrile) as an initiator to give the copolymers I – VI in good yields. The copolymer compositions were obtained using related ¹H NMR spectra and the polydispersity indices of the copolymers determined using gel permeation chromatography (GPC). Tris(trimethylsilyl)methyl (Tsi=trisyl) groups were then covalently attached to the obtained copolymers as side chains by ring opening reaction between excess of TsiLi and expoxide groups of GMA units to give the copolymers I_Tsi – VI_Tsi in good yields. In the coupling reaction, the TsiLi reacted selectively with the epoxy groups of the backbone polymer rather than with the carbonyl groups of the backbone. This method of preparing functionalized silanes is limited by the readiness with which TsiLi abstracts a proton, if one is available, rather than attacks at carbon. In addition in the reaction with epoxides, the product alkoxide can transfer a silyl group from carbon to oxygen or ring opening polymerization. However these were shown not to occur at the conditions of interest here. The epoxy group possesses a higher reactivity for the TsiLi than the ester and chloromethyl groups. The ring opening reaction between the epoxy group and the TsiLi is simple and fast. All the resulted polymers were characterized by FT-IR and ¹H NMR spectroscopic techniques. The glass transition temperature (Tg) of all copolymers was determined by differential scanning calorimetry (DSC) apparatus. All the polymers containing trisyl groups showed a high glass transition temperature in comparison with unmodified copolymers (I – VI). Attaching the tris(trimethylsilyl)methyl group to macromolecular chain should lead to important modifications of polymer properties such as gas permeability and perm selectivity parameters.     

Analytical equations for flow transient's characteristics of pool-type gravity driven research reactors

Analytical equations have been developed to accurately predict the coolant flow rate vs. static head relationship of an MTR pool-type gravity driven research reactor from its friction-loss characteristics. Excellent agreement between theory and existing experimental data was obtained. These equations provide the basis for more rapid and accurate analysis than presently employed more cumbersome trial-and-error methods.     

On the rotational operators in protein structure simulations

The reduction of the computational complexity of the algorithmsdealing with protein structure analysis and conformation predictionsis of prime importance. One common element in most of thesealgorithms is the process of transforming geometrical informationbetween dihedral angles and Cartesian coordinates of the atomsin the protein using rotational operators. In the literature,the operators used in protein structures are rotation matrices,quaternions in vector and matrix forms and the Rodrigues–Gibbsformula. In the protein structure-related literature, the mostwidely promoted rotational operator is the quaternions operator.In this work, we studied the computational efficiency of themathematical operations of the above rotational operators appliedto protein structures. A similar study applied to protein structureshas not been reported previously. We concluded that the computationalefficiency of these rotational operators applied to proteinchains is different from those reported for other applications(such as mechanical machinery) and the conclusions are not analogous.Rotation matrices are the most efficient mathematical operatorsin the protein chains. We examined our findings in two proteinmolecules: Ab1 tyrosine kinase and heparin-binding growth factor2. We found that the rotation matrix operator has between 2and 187% fewer mathematical operations than the other rotationaloperators. Received June 6, 2003; revised July 17, 2003; accepted August 20, 2003.     

POLYNUCLEAR AROMATIC COMPOUNDS IN COAL AND OIL SHALE WASTEWATER: AN ENVIRONMENTAL CONCERN

A solvent refining coal liquefaction process recycle water (No. 3) from Du Pont, Washington, a true in-situ oil shale retort water (Omega-9) from Rock Springs, Wyoming, and a ten-ton unit simulated in-situ oil shale retort water (No, 16) from Laramie, Wyoming, were subjected to solvent extraction procedure and subsequent instrumental analysis including: (a) high performance liquid chromatography (HPLC) of polynuclear aromatics (PNA's) having more than four rings; (b) capillary gas chromatography (GC) of low molecular weight volatile PNA's; and (c) gas chromatography-mass spectrometry (GC-MS) for complementary identification of PNA's having functional and heterocyclic modifications.

A total of 41 PNA's were identified. Identification of 28 PNA's in the coal derived water (No. 3) was attained, whereas that of the true in-situ retort water (Omega-9) and the simulated retort water (No. 16) were 24 and 18, respectively. Thirteen PNA's were found to be common to all three wastewater samples. Thirteen PNA's were exclusively found in sample No. 3 whereas that of samples Omega-9 and No. 16 were 8 and 4, respectively. It was estimated that the concentration of PNA's in all samples ranged from traces to 30.0 ppb.