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Light olefins such as ethylene, propylene and butylene are mainly used in the petrochemical industry. Due to the growing need for light olefins in the industry and the future shortage of petroleum resources, the process of converting methanol to olefins (MTO) using non-oil sources has been considered as an alternative. Coal and natural gas are abundant in nature and the methods of converting them to methanol are well known today. Coal gasification or steam reforming of natural gas to produce synthetic gas (CO and hydrogen gas) can lead to methanol production. Methanol can also be catalytically converted to gasoline or olefins depending on the effective process and catalyst factors used. Due to the use of crude methanol in the MTO unit and because the feed does not require primary distillation, if the MTO unit is installed alongside the methanol unit, its capital costs will be reduced. The use of methanol can have advantages such as easier and less expensive transportation than ethane. Among the available catalysts, SAPO-34 is the most suitable catalyst for this process due to its small cavities and medium acidity. One of the problems of MTO units is the rapid deactivation of SAPO-34, which can also be affected by the synthesis factors, so it is possible to optimize the catalyst performance by modifying the synthesis conditions. In this article, we will introduce the MTO process and the factors affecting the production of light olefins.

The linear complexity and the error linear complexity are two important security measures for stream ciphers. We construct periodic sequences from function fields and show that the error linear complexity of these periodic sequences is large. We also give a lower bound for the error linear complexity of a class of nonperiodic sequences.

Two tweezer-like anion receptors 2,2′‑bis(2‑cyano‑2‑phenylvinyl)‑5,5′‑dimethyl dipyrromethane (1) and 2,2′‑bis[2‑cyano‑2‑(4‑nitrophenyl)vinyl]‑5,5′‑dimethyl dipyrromethane (2) were synthesized in good yields, via a facile condensation of diformyldipyrromethane and the appropriate phenylacetonitrile. Anion recognition properties of these receptors were studied in detail in DMSO solution, by means of UV–vis and 1H NMR titration techniques. The obtained results indicated that receptor 2 containing a terminal nitro group exhibited the strong and selective binding to biologically important fluoride and dihydrogenphosphate ions over other anions. In addition, the binding strength of receptor 2 with fluoride was enhanced by a factor of 18, relative to receptor 1 lacking the nitro group. Remarkably, the presence or absence of nitro group within receptor compounds also had a great influence on the anion-binding selectivity. In particular, a distinct color change of DMSO solution of receptor 2 was observed only upon addition of fluoride, showing the potential of 2 acting as an effective colorimetric sensor for the detection of fluoride anion.

Most multilayer sandstone reservoirs in the Bohai Sea have already entered the middle or high water cut production stage with large amounts of remaining oil being scattered distributed. Therefore, there is an urgent need to find a suitable countermeasure to reduce water cut and increase oil recovery. In this study, taking the narrow-channel reservoirs in the M oilfield as an example, we qualitatively described the sand body scale and the contact relationships between different sand bodies, in addition to carefully analyzing the material base and remaining oil distribution characteristics. Accordingly, we proposed a countermeasure based on the injection-production structural adjustment to reduce water cut and increase oil recovery from high water cut, narrow-channel reservoirs. Herein, three optimization strategies were developed based on the proposed development mode: a seepage field optimization strategy was developed based on the quantified injection-production index; a well pattern optimization strategy for narrow-channel reservoirs was developed to overcome the production energy refueling problem; an injection-production measure optimization strategy was developed to tap the different types of remaining oil. Additionally, the well pattern optimization and injection-production optimization strategies were integrated to optimize and adjust the seepage field system. The findings reported herein this paper help understand the development of similar offshore oilfields with a high water cut.

More and more researches have been carried out recently on Weigh-In-Motion (WIM) technology for solving the traffic safety problems caused by overload. In this article, we aim to study the measurement accuracy of the WIM system. Based on the electromechanical theory and elastic half-space method, we establish a theoretical model of multi-layer structure to investigate the correlation between the output voltage of the piezoelectric sensor and the applied force. In addition, we performed cyclic and moving load experiments to verify the accuracy of the analytical calculations. The load magnitude identified by this theoretical model matched the experiments very well, which shows that this model is effective for the WIM system. In addition, we proved that the load frequency is an important factor affecting the measurement accuracy of the sensor, which further enables us to design more suitable sensors for certain use scenarios.

In this study, polypropylene (PP) foams were prepared with 1.0 wt% of cucurbit[6]uril (Q[6]), zinc acetate (Zn(Ac)2), Zn@Q[6] (a supramolecular compound synthesized from Q[6] and Zn(Ac)2), or a mixture of Zn(Ac)2 and Q[6] (weight ratio of 1:1) through injection molding in the presence of a chemical blowing agent, azodicarbonamide. The effect of the additions on the crystallization behavior and foaming performance of PP and the mechanical characterizations of the foaming samples were determined. The results showed that the additions can change the crystallization type from homogeneous to heterogeneous, increase the crystallization rate and shrink the size but increase the density of spherulites. Among the additions, Q[6] most significantly altered the crystallization properties. Scanning electron microscopy (SEM) images revealed that the PP foaming performance can be improved by Zn(Ac)2 addition at a lower temperature (175°C); however, further increasing the temperature had an undesirable effect. Q[6] exhibited the optimum foaming improvement effect on PP in a wide temperature range (175–195°C). Adding nanoparticles also enhanced the tensile properties, flexural strength and impact strength of foaming PP at low temperatures. However, with increasing temperature, the poor cell structure demonstrated undesirable effects in terms of tensile strength, flexural strength and impact strength.

Conventional production optimization for waterflooding reservoirs relies on full-scale reservoir simulators and repeated simulation runs to calulate gradient information. These factors lead to expensive computational cost. Different from the conventional optimization, in this paper, a novel waterflooding optimization method is developed by running a data-driven interwell numerical simulation model with flow-path tracking (INSIM-FPT) in three dimensions. With the application of flow-path tracking strategy, the more-accurate calculations of dynamic allocation factors and control pore volumes can be obtained from INSIM-FT-3D model. Moreover, based on the INSIM model, we define producer-centered production efficiency of wells with multiple perforations and propose a rapid waterflooding optimization method. The optimized well production rates and injection rates are obtained with the help of the oil cut and the existing injector-centered allocation factors derived from INSIM model. The new optimization method requires only one time forward run without repeated iterative calculations. And the optimization is completely based on reservoir-engineering points of view, making it easy to explain oil increment mechanisms. Finally, a synthetic case and the other large-scale field case is established to test its optimization performance.

In this study, a supramolecular compound (Zn@Q[6]) was synthesized by cucurbit[6]uril (Q[6]) and zinc acetate [Zn(Ac)2] through a chemical method. Powder X-ray diffraction and X-ray crystallography analyses were conducted to confirm the crystallographic structure of Zn@Q[6]. Results showed that the four-coordinated Zn(II) centre coordinated with four chloride ions, and each [ZnCl4]2− anion interacted with three Q[6] molecules through hydrogen bonds between Q[6] and the chloridion of [ZnCl4]2−. Subsequently, Zn@Q[6], Zn(Ac)2 and the mixture of Zn(Ac)2 and Q[6] were introduced respectively as nucleating agents into polypropylene (PP) microcellular injection using azodicarbonamide (ADC) as a chemical blowing agent. Compared with Zn(Ac)2 and the mixture of Zn(Ac)2 and Q[6], improved cell morphology was obtained with addition of Zn@Q[6] obviously at relatively high injection temperatures, except 175 °C, at which no obvious improvement in Zn@Q[6] was observed. The underlying mechanisms were then discussed by thermal and rheological analyses. Zn@Q[6] could be a novel inorganic–organic nucleating agent that can suppress the catalysis activity of Zn(II) for the decomposition of ADC and PP.

Shale gas reservoirs demonstrate low matrix porosity and permeability, and show obvious heterogeneity due to the existence of natural fractures. During the production process, fracturing fluid can easily invade the reservoir and result in a low fracturing flowback rate. The existing numerical methods are troublesome and have poor convergence. Therefore, it is necessary to develop a new approach to study the gas-water two-phase flow in shale gas reservoirs. In this paper, fractal theory is used to quantitatively characterize the heterogeneous fractures. A Mathematical model considering fractal induced-fracture distribution and gas-water two-phase flow in shale reservoirs is established. The meshless weighted least squares (MWLS) method is applied, for the first time, to the numerical simulation of gas-water two-phase flow in multi-fractured horizontal wells of shale gas reservoirs. Based on the moving least squares approximation, the variation principle is derived in detail. A numerical model of gas-water two-phase flow in the shale gas reservoir fracturing horizontal well based on the meshless method is obtained. The gas and water production of fractured horizontal shale gas wells are predicted by the model. The model simulation results are found to be in good consistent with the mathematical calculation results obtained through finite difference method. but the proposed new approach shows significant higher calculation efficiency. In addition, by applying this new approach, The influences of fracture distribution, initial water saturation, and reservoir reconstruction degree on the utilization range and production were also systematically compared and analyzed. The results showed that the smaller the fracture fractal index a in the reservoir reform area, the lower the pressure, the higher the daily gas production and the daily water production, indicating that the fracture network is densely distributed and the production effect is better. The larger the initial water saturation resulted in the greater flow resistance of the gas phase and the decrease of daily gas production. When the fracture spacing decreases in reservoir reconstruction, the daily gas production increases, but the increase range is gradually reduced and it has little effect on the daily water production.

Since overload has become the main potential safety hazard for aging bridges, management of traffic load information is of great significance in safety insurance of bridges. Here, an array of lead zirconium titanate (PZT) sensors is utilized to capture the dynamic responses of beam bridge due to moving load, for which the details are identified based on electromechanical analysis and structural dynamics. The precision and feasibility of the proposed method are validated by experimental tests for a simply supported and a continuous steel beam respectively. Results show that the PZT sensor has the advantage of self-driving, fast response and high precision, which makes it possible for wireless sensing technology. Results also reveal that dynamic responses of the beam can reflect effectively the moving speed and magnitude of the moving force when the load approaches to the mid-span. Furthermore, the proposed method is applicable for different beam structures and insensitive to the noise interference. The current method may provide guidance for bridge moving load identification.

The output performance of the current origami inspired Triboelectric Nanogenerator (TENGs) are limited by the simple origami pattern used as the TENGs base. Here, we propose a kind of origami tessellation (OT) base to enhance the electric output performance of TENG and facilitate its application in road pavement for energy harvesting. The OT base provides multi layers facets to install tribo-pairs and can be driven by very small stimulation owing to the resilience of the structure. It can be operated effectively under either traction or compression depending on the initial configuration of the OT base. Besides, the foldability of the OT base makes easily the developed devices to be fitted thin gap in the road pavement. A series of mechanical tests are carried out to study the output performance of a quadrangular prism shape OT-TENG based on the Arc pattern under different boundary conditions and frequencies. To guarantee the motion synchronicity of the OT base, a strip-shape OT-TENG based on the Miura pattern is designed to obviously increase the output performance as the number of the tribo-pairs increases. Then, the tracking board test shows the potential application of the OT-TENGs for pavement vibration energy harvesting. By constructing a two-dimensional network of the OT-TENGs in pavement, the devices will provide a feasible green energy to meet the energy need of the intelligent transportation systems in the future. The outcomes of this work offer a novel OT-TENG design with great potential to dramatically enhance the output performance of TENGs devices in more general shape space and more flexible environment for vibration energy harvesting.

With the development of smart grid, demand-side resources (DSR) will play an increasingly important role in the power balance of supply and demand. In addition, the requirement of a low-carbon smart grid means some policy backgrounds, such as carbon emissions trading (CET), should not be ignored. Under these circumstances, it is a good idea to construct a novel unit commitment (UC) model. This paper proposes a model that not only takes advantage of various resources on the demand side, such as electric vehicles, demand response, and distributed generation, but also reflects the effects of CET on generation schedule. Then, an improved particle swarm optimization (IPSO) algorithm is applied to solve the problem. In numerical studies, we analyze the impacts of DSR and CET on the results of UC, respectively. In addition, two meaningful experiments are conducted to study the approaches to allocate emission quotas and the effects of price transmission mechanism.

Scanning Electro Microscope (SEM) images illustrate the variety of possible pore shape in organic matter of shale reservoirs. The size of the pores with different geometries is at nanoscale (10–100 s nm), hence the ratio of wetted surface area to the volume of pores (specific surface area, SSA) is high. For the systems with high SSA the collisions between gas molecules and pore walls become significant, therefore, fluid flow is not dominantly controlled by the bulk flow, i.e., fluid-wall surface interaction becomes important. Most shale permeability models assume circular nanopores that results in poor prediction of permeability. We present a novel analytical apparent porosity and permeability model to model gas storage and permeability in shale gas reservoirs with noncircular nanopores. The SSA and the aspect ratio of height to the width of noncircular nanopores, were both used in our model to couple gas storage and transport capacity. We validated our model with permeability values calculated from pore network simulations of five shale samples from Jianghan Basin of China. The results showed that sharp edges in nanopores could dramatically affect permeability. For examples, the noncircularity deviation of gas flow in a rectangular nanopore is more than an equivalent nanopore with elliptical cross-section. The assumption of circular cross-section nanopores in estimating apparent porosity and permeability could impose up to 55% error depending on the pore geometry.

Unlike existing studies focused on the causal relationship between electricity consumption and economic growth at the macro level, this paper uses monthly data from January 2006 to December 2015 and applies the correlation coefficient, as well as Kullback-Leibler (KL) divergence, to study the time difference relationship between sectoral electricity consumption and economic growth. The empirical results draw some main findings as follows: First, the time difference relationships show diversity at the sector level but will form a kind of overall characteristic between economic growth and total electricity consumption. Secondly, not all sectors have a remarkable correlation between sectoral electricity consumption and economic growth as only part of them have reasonable values to describe the time difference relationship. Thirdly, the results present both diversity and aggregation at the industry level, while lagging sectors mainly concentrate in the manufacturing industry. The relationship between sectoral electricity consumption and economic growth can be further explored and described from a new perspective based on the results. Further, the trend of economic development and sectoral electricity consumption can be predicted to help policy-makers formulate proper policies.

Numerous optimization variables cause the optimization of large-scale field development challenging, which can be overcome by constraining wells to be within patterns and optimizing the parameters relevant to the pattern type and geometry. In this study, a new method incorporating well pattern optimization and production optimization for unconventional reservoirs is presented. By defining a quantitative well pattern description approach, we develop the geometric transformation parameters to quantify well pattern operations (e.g., rotation, shear, especially translation) to change the geometric shape of well patterns including five-spot, inverse seven-spot and inverse nine-spot well pattern. In contrast, a variety of optimization algorithms can be applied to accomplish the optimization of well pattern problems but the computational cost is large for many algorithms. Therefore, we also propose a general upscaling stochastic approximation algorithm (GUSA), which is an improved approximate perturbation gradient algorithm, to realize the combination of well pattern optimization and production optimization simultaneously. It is proved that both the gradient formulation of SPSA algorithm and EnOpt algorithm are the special form of the general approximate perturbation gradient. Afterwards, the synthetic cases (homogeneous and heterogeneous models) and actual unconventional field cases are discussed based on the three mentioned well pattern types. The detailed optimization results show that the presented coupling method can achieve the optimization by transforming well pattern geometry, reducing the total number of wells and adjusting the field injection rate, which is proved to be effective. In sum, this coupling method provides an efficient optimization procedure combing the well pattern optimization and production optimization for practical field development.

In this study, polypropylene (PP) foams were prepared with cucurbit[6]uril (Q[6]) used as a novel nucleating agent through a microcellular injection molding foaming process. The effect of Q[6] content (0.5–2.0 wt %) on the foaming behavior, as well as thermal, rheological and mechanical characterizations of the PP/Q[6] (PQ) samples were performed. According to scanning electron microscopy (SEM) images, the microstructure of foams exhibited a smaller cell size, higher cell density, and more homogeneous distribution of cells at a higher Q[6] content. It was found that the peak temperature of crystallization, the crystallinity and the crystallization rate of PP can be obviously improved by adding a low content of Q[6] (0.25–1.0 wt %), whereas further increasing the content of Q[6] (2.0 wt %) would disfavor the effect. With increasing the Q[6] concentration, the PQ composites had higher complex viscosities at low frequencies and higher modulus than that of PP except the content of 2.0 wt %. Furthermore, the introduction of Q[6] into PP can produce a mild increase in tensile strength, flexural strength and impact strength of PQ foams. This can be due to the well dispersion of Q[6], good compatibility between PP and Q[6], as well as the improvement of the cell morphology. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44538.