Hybrid intelligent strategy for multifactor influenced electrical energy consumption forecasting

ABSTRACT

This paper proposes a novel hybrid strategy based on intelligent approaches to forecast electricity consumptions. The proposed forecasting strategy includes three main steps: (a) the evaluation of a correlation coefficient for socio-economic indicators on electric energy consumptions, (b) the classification of historical and socio-economic indicators using the proposed feature selection method, (c) the development of a new combined method using Adaptive Neuro-Fuzzy Inference System and Whale Optimization Algorithm to predict electrical energy consumptions. The simulation results have been tested and validated by real data sets achieved within 1992 and 2010 in two pilot cases in a developing country (Iran) and a developed one (Italy). The research findings pinpointed the greater accuracy and stability of the new developed method for electrical energy consumption forecasting compared to existing single and hybrid benchmark models.     

Model-order reduction using variational balanced truncation with spectral shaping

This paper presents a spectrally weighted balanced truncation (SBT) technique for tightly coupled integrated circuit interconnects, when the interconnect circuit parameters change as a result of statistical variations in the manufacturing process. The salient features of this algorithm are the inclusion of the parameter variation in the RLCK interconnect, the guaranteed passivity of the reduced transfer function, and the availability of provable spectrally weighted error bounds for the reduced-order system. This paper shows that the variational balanced truncation technique produces reduced systems that accurately follow the time- and frequency-domain responses of the original system when variations in the circuit parameters are taken into consideration. Experimental results show that the new variational SBT attains, in average, 30% more accuracy than the variational Krylov-subspace-based model-order reduction techniques.     

Preparation and characterisation of hydroxyl-terminated polybutadiene-based polyurethane/graphene nanocomposites

Polyurethane nanocomposites based on hydroxyl-terminated polybutadiene and graphene with different formulations were cured using toluene diisocyanates. The rheological, physical, mechanical, thermal and morphological properties of the nanocomposites were investigated. The viscosity of the samples increased rapidly with graphene content. However, the kinetic rate of the curing process was lower for the nanocomposites in comparison to the neat matrix. The mechanical properties showed a successive increase in the tensile strength and reduction in elongation at break with an increase in graphene content. The highest value of the modulus, density and degradation temperature was obtained for the nanocomposite with 1?wt-% graphene. The hardness properties of the nanocomposites enhanced with curing time. The morphological properties of the nanocomposites are also investigated with the field emission scanning electron microscopy which confirmed the agglomeration occurrence at the high graphene contents.     

Synthesis of silica-supported ZnO pigments for thermal control coatings and analysis of their reflection model

A spacecraft in orbit undergoes extreme temperature cycling, space radiations, and other extreme conditions that can potentially raise the temperature of spacecraft to harmful levels. Hardware and sensitive detectors utilized in spacecrafts require that temperatures be maintained within specified ranges. Thermal control coatings (TCCs) help to maintain the thermal equilibrium of the spacecraft at a level acceptable for vital components. This is done by employing the diffused reflection of all effective ultraviolet (UV), visible (VIS), and near-IR (NIR) wavelengths of solar radiation and emitting the infrared (IR) energy. The most commonly used TCCs have utilized potassium silicate as the binder and ZnO as the pigment (Z-93), but absorption of UV light by ZnO pigment affects the ideal scheme of these TCCs. In the present study, silica-supported zinc oxide particles with different ZnO contents were synthesized as pigments for white thermal control coatings and the optimized one was selected based on the experimental determination of the optical properties of the prepared coatings. The results revealed that the optimized TCCs containing pigment with the zinc to silicon ratio of 1.91 had better reflection and emission properties in comparison with Z-93, due to the improvement in the refractive index and the dispersion quality of pigment. Then, the scattering properties (S) of the synthesized pigments and ZnO in TCC were investigated based on the reflectance data, according to the Kubelka–Munk analysis. The general trend in scattering coefficients for each formulation showed the same shape, such that with the increase in S values, the zinc to silicon ratio of pigments was raised too. Also, this trend revealed that scattering was more efficient at longer rather than shorter wavelengths. For Z-93, this trend was completely opposite. Also, S values for Z-93 in the wavelength range of 200–400 nm were around zero, while for the prepared coatings, this was not the case. Finally, the statistical nonlinear regression method was utilized to prepare a model for reflectance as a function of the zinc to silicon ratio of pigments and the wavelength of light.     

Low Temperature Catalytic Oxidation of Binary Mixture of Toluene and Acetone in the Presence of Ozone

This work reports on gas phase catalytic ozonation of a binary mixture of toluene and acetone and compares it with catalytic ozonation of single component acetone and toluene. Catalytic ozonation was conducted at 25–90 °C on MnO_x/γ-Al₂O₃ catalyst. XANES and EXAFS were used to identify formal oxidation state of Mn and local structure of manganese oxide in the catalyst. Absorption energy of Mn K-edge of the catalyst was determined to be 6553.86 eV indicating that the majority of manganese in the catalyst was in 3+ oxidation state. Catalytic ozonation in the mixture was favourable for removal of toluene, and repressive for removal of acetone. This was due to (a) lower apparent activation energy of catalytic ozonation of toluene (E_{a, Toluene}?=?31 kJ mol^?1?<?E_{a, Acetone}?=?40 kJ mol^?1) that led to higher reactivity of toluene with active oxygen species, and (b) inhibitory effect of accumulated carbonaceous byproducts on the acetone removal. Increase of reaction temperature enhanced conversion of both compounds, decreased the gap between toluene and acetone conversions, and improved CO_x yield. Overall degradation pathway of toluene and acetone in the mixture was determined by identifying the reaction intermediates and carbonaceous deposits on the catalyst. The observed mixture effects helped to understand potentials and limitations of catalytic ozonation in treating mixture of VOCs, which will aid in developing commercial air treatment systems.

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Synthesis of a novel sulfonated poly(amide‐imide) and its application in preparation of ultrafiltration PES membranes as a modifier

Sulfonated poly(amide‐imide) (SPAI) copolymer was synthesized, characterized, and blended into poly(ether sulfone) (PES)/dimethylacetamide casting solutions to prepare ultrafiltration membranes. Different weight ratios of the copolymer (0–10 wt %) were mixed in the PES casting solution. The analyses of contact angle and attenuated total reflection‐Fourier transform infrared spectra were used to study hydrophilicity and physicochemical properties of the membrane surface, respectively. The membranes were further characterized by scanning electron microscopy images, ultrafiltration performance, and fouling analyses. The outcomes showed that addition of the SPAI in the PES matrix improved considerably the membranes hydrophilicity. Moreover, with increasing SPAI concentration, the porosity, flux recovery ratio, and pure water permeability of the modified membranes were improved. The pure water flux was increased from 3.6 to 12.4 kg/m² h by increasing 2 wt % SPAI. The antifouling property of the modified PES membranes against bovine serum albumin, tested by a dead‐end filtration setup revealed that bovine serum albumin rejection of the obtained membrane was also enhanced and the antifouling properties of the blending membranes were improved. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46477.     

Single-machine earliness–tardiness scheduling with two competing agents and idle time

Two-agent scheduling has gained a lot of research attention recently. Two competing agents who have their own objective functions have to perform their respective set of jobs on one or more shared machines. This study considers a two-agent single-machine earliness and tardiness scheduling problem where jobs have distinct due dates and unforced idleness in between any two consecutive jobs is allowed. The objective is to minimize the total earliness and tardiness of jobs from one agent given that the maximum earliness–tardiness of jobs from the other agent cannot exceed an upper bound. In other words, each job from the second agent has a hard due window, whereas each job from the first agent will incur a penalty if completed either before or after its due date. Two mathematical models of the problem are presented, and several necessary optimality conditions are derived. By exploiting the established dominance properties, heuristic algorithms are developed for the problem. Finally, computational experiments are conducted to assess the models and heuristic procedures.     

A novel polyurethane modified with biomacromolecules for small-diameter vascular graft applications

There is a growing demand for small-caliber tissue-engineered vascular grafts to replace damaged vessels. Fabricated scaffolds are unable to precisely mimic the mechanical properties of native vessels, provide long-term patency and support cell adhesion and growth, in particular support endothelialization. In this study, a new biodegradable poly(ether ester urethane) urea (PEEUU) was synthesized. The synthesized polyurethane was then functionalized by introducing free amino groups through aminolysis for further surface modification by immobilization of biomacromolecules on the surface of vascular grafts. The modified surfaces were then characterized using attenuated total reflectance-Fourier transform infrared spectroscopy, water contact angle measurement and atomic force microscopy. The mechanical properties of the fabricated scaffolds were analyzed, revealing mechanical properties close to that of the natural vessels. Surface modifications led to improved cell–scaffold interactions, showing appropriate cell attachment and function on the scaffolds. A confluent layer of endothelial cells was formed on biomacromolecule-immobilized PEEUU vascular grafts. The preliminary results of this study demonstrated that the new polyurethane modified with biomacromolecules can be considered as a candidate material for vascular tissue engineering application with capability to support endothelialization of fabricated vascular grafts.     

Enhancement of Critical Current Density of MgB<Subscript>2</Subscript> by Glutaric Acid Doping: a Simultaneous Improvement on the Intrinsic and Extrinsic Properties

In this study, we report an enhancement of critical current density of bulk MgB₂ superconductors by glutaric acid (C₅H₈O₄) doping. The effects of glutaric acid doping on MgB₂ lattice resulted in a record self-field J _c of the order of 10⁶ A/cm². A simultaneous improvement in the connectivity, pinning force, and H _c2 is the major factor that determined excellent J _c performance. X-ray diffraction analysis showed that samples were single-phase MgB₂ with a minor trace of impurities. A dramatic change in grain morphology and homogeneity in grain distribution was found in the SEM images of doped samples. We observed that homogeneity in grain distribution played a crucial role in the connectivity and the upper critical field (H _c2) of the doped samples. We were able to introduce a new dopant through a two-step mixing approach which is suitable to overcome the degradation of low field and self-field J _c reported for carbon-doped MgB₂ superconductor samples.