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A dynamic surface pattern with tunable liquid crystalline texture and fluorescence in response to external stimulus can enable information recording and reading. Therefore, such patterns are widely used in the field of information security and anti-counterfeiting. A higher level of security in anti-counterfeiting is extremely desirable but challenging, herein, the chiral liquid crystalline networks (CLCN) used for anti-counterfeiting displaying both dynamic reversible Grandjean textures and fluorescence were dexterously designed and prepared by graft copolymerization of polymethylhydrosiloxane (PMHS), nematic liquid crystal M1, chiral crosslinker M2 and organic fluorescent pyrene compounds M3. The CLCN can emit blue-fluorescence when irradiating with ultraviolet light. More importantly, the Grandjean textures and fluorescence can be simultaneously and precisely adjusted by temperature. The as-prepared CLCN display reversible Grandjean textures during the heating and cooling process from the intrinsic chiral arrangement of CLCN. The discrete pyrene chromogenic segments in CLCN matrix enable the tunable photoluminescence by temperature, furthermore, the CLCN present highly sensitive photoluminescence evolution. The dynamic reversible Grandjean textures and fluorescence make the smart materials promising candidates in anticounterfeiting, providing a versatile strategy to fabricate intelligent optical anti-counterfeiting materials.

Development of efficient catalyst for conversion of benzyl alcohol to benzaldehyde using molecular oxygen is of great importance in virtue of the economic and environmentally friendly superiority. In this study, a cobalt-based zeolitic imidazolate framework, ZIF-67, has been used as precursor to synthesize different catalysts for study in benzyl alcohol oxidation by air. The catalysts were characterized by XRD, SEM, ICP-MS, N2 adsorption-desorption and XPS. The cobalt oxide catalyst, which was obtained via calcination of ZIF-67 in air, showed low activity and selectivity toward benzaldehyde. While the Co@CN, prepared from pyrolysis in argon, exhibited good activity and recyclability under mild conditions. The results suggested that the cobalt species, either metallic cobalt or Co2+, were the main active sites. In addition, the nitrogen species also played a role for the efficient conversion of benzyl alcohol.

A promising Ni-MoOx bifunctional catalyst for halide-free methanol carbonylation is developed by H2-reduction of NiO-MoO3/SiO2 obtained via facile impregnation method. Catalyst performance is strongly dependent on the calcination/reduction temperature. Over the preferable NiMo-350-600/SiO2 catalyst obtained by calcining at 350 °C and subsequently reducing at 600 °C, a methanol conversion of 4.2 % and acetyls space-time yield of 1.37 mol kgcat−1 h−1 are achieved with 22.1 % selectivity to acetyls at 290 °C and 3 MPa. Co-existence of Ni0 and MoOx (especially MoO2) markedly decreases formation of dimethyl ether (DME) and reversely increases acetyls formation, in nature, due to the catalyst acidity modulation and the partial electron transfer from Ni0 to MoOx that tunes the CO adsorption strength on Ni0 sites. MoO3 and NiMoO4 are both favorable for formation of acetyls and DME whereas the latter mainly accounts for DME formation. MoNi4 alone favors methyl formate formation while together with MoO2 enhancing DME production.

Sustainable transformation of methane into methanol feedstock syngas is a promising direction in future energy generation. A monolithic SiC-foam (SiC-foam, denoted as SCf) supported structured Ni-SrO composite nanomaterial was prepared via reducing the SrNiO3 perovskite. The Ni-SrO/SCf displays a stronger resistance to Ni-sintering/coke-deposition than the unmodified Ni/SCf due to its uniform Ni distribution as well as the strong Ni-SrO interaction. In the presence of Ni-SrO/SCf sample at a gas hourly space velocity (GHSV) of 24,000 mLCH4 CO2 gCat−1 h − 1 and an operating temperature of 850 °C, the initial conversion rate of biogas (CH4/CO2) was 70/94%, which gradually dropped to 55/72% within 40 h, but its activity remained stable for the next 60 h. By contrast, the conversion rate of biogas (CH4/CO2) in the presence of Ni/SCf sample was decreased rapidly from 60/80 to 50/65% within 20 h, due to the severe coke deposition and Ni-sintering.

Information-centric networking (ICN) is one of the promising candidates for the future network architecture. In-network caching deployed on the routers is the key feature in ICN, which can improve the network performance, off-load network traffic, and further reduce the latency perceived by end users. The appropriate cache capacity assignment and deployment are important factors in ICN performance optimization. In this paper, a fine-grained cache deployment scheme is proposed for the access network based on the traffic load in order to determine the cache location and the cache capacity on the chosen routers simultaneously. Under the total capacity preplanned, we first organize the nodes in access network into hierarchical structure based on the node connectivity. And then a certain cache capacity is decided to deploy on the routers in a hierarchical layer with the best performance each time, until the total capacity is successfully deployed in the ICN network. The simulation results show that the fine-grained cache deployment scheme is always better than the content distribution network-like scheme or edge caching policy, in which the cache capacity is only deployed on the boundary routers.

A facile strategy is reported for engineering layered double hydroxides (LDHs)-derived nanocomposite catalysts from nano-to macro-scales in one step, via the Al 2 O 3 /water interface-assisted method to embed LDHs onto monolithic substrates (such as thin-felt microfibrous structure using 22 μm FeCrAl fibers or 20 μm stainless steel fibers and SiC foam) followed by calcination to transform LDHs to nanocomposites. Such approach achieves unique integration of tunability and homogeneous distribution of catalytic components, enhanced heat/mass-transfer, self-supported feature, and high permeability, thus exhibiting tremendous potential for application in harsh reactions. For example, the thin-felt NiO MgO Al 2 O 3 /FeCrAl-fiber catalyst derived from NiMgAl-LDHs/Al 2 O 3 /FeCrAl-fiber offers high activity and stability for the high throughput and exothermic catalytic oxy-methane reforming: 87–90% methane conversion and 91–93/90–92% H 2 /CO selectivities at 700 °C within 300 h testing, using a high gas hourly space velocity of 72 L g −1 h −1 .

Self-supported NiO-MOx-Al2O3 (M = Ce or Mg) nanocomposites mounted on a Ni-foam (110 PPI) as the monolithic structured catalyst have been developed for the high throughput catalytic partial oxidation of methane to syngas. The catalysts are obtainable by direct growth of NiAl layered double hydroxides nanosheets and subsequent impregnation with boehmite sol containing Al-Ce or Al-Mg nitrates. Such catalysts are highly active and selective with promising stability in the title reaction, for example, the NiO-CeO2-Al2O3/Ni-foam achieves a high methane conversion of 86.4% with 91.2%/89.0% selectivities to H2/CO and is stable for at least 100 h at 700 °C and a high gas hourly space velocity of 100 L g−1 h−1. Thanks to a feasible CeO2↔CeAlO3 chemical cycling that is able to promote the O2 activation to create an oxidative environment around Ni particles, carbon formation rate is dramatically suppressed by a factor of at least 5 compared to the base catalyst.

BACKGROUND Catalytic distillation (CD) has been received as an inviting green chemical process for numerous catalytic esterification reactions. Rendering novel structured CD packings is particularly desirable but remains challenging. RESULTS We present a microfibrous-structured HZSM-5 solid acid catalyst as CD packings and demonstrate its separation and esterification reaction efficiency for producing ethyl acetate from acetic acid and ethanol. The factorial design based on response surface methodology is employed for fast determination of optimum reaction conditions, which is working effectively and efficiently. Such structured catalyst packings are obtained by direct growth of zeolite onto the θ-ring analogues shaped from a microfibrous-structure consisting of 15 vol% 20 µm stainless-steel-fiber (SS-fiber) and 85 vol% voidage. CONCLUSION The SS-fiber@HZSM-5 packings provide a unique combination of instantaneous distillation and desired catalytic properties with respect to stability, adequate acidic sites and high mass/heat transfer, and therefore work efficiently and effectively. High total (95.9%) and actual (90.9%) yields of ethyl acetate with 89.8% purity are achievable while the high CD efficiency was well-preserved after at least 240 h over 30 consecutive batch runs.

Microfibrous-structured SS-fiber@beta composites are synthesized by coupling dip-coating method with a seed-assisted dry-gel conversion method. The beta crystals in zeolite shell are formed by growth on the surface of pre-added beta seeds and TEAOH-induced nucleus. One interesting point is that this approach is working highly effectively and efficiently even at high dry gel SiO 2 /Al 2 O 3 ratio of 200 (corresponding to 207 in the beta zeolite shell). Such SS-fiber@beta composites show great potentials for the heat/mass transfer limited reactions due to their hierarchical porosity, small crystals, controllable acidity as well as our distinctive microfibrous-structured design.

The Mn2O3-Na2WO4/SiO2 catalyst is the most promising one among the enormous catalysts for the oxidative coupling of methane (OCM) but only at above 800 °C. No doubt that lowering temperature of the OCM process is at the forefront of this catalysis field. A promising low-temperature active and selective TiO2-doped Mn2O3 Na2WO4/SiO2 catalyst, consisting of 6 wt% TiO2, 6 wt% Mn2O3, 10 wt% Na2WO4 and SiO2 in balance, is developed by solution combustion synthesis (SCS) method. This catalyst is capable of converting 20% CH4 with 70% selectivity to C2-C3 hydrocarbons even at 700 °C (catalyst bed temperature) and is stable for at least 250 h without deactivation sign, for a feed gas of 50% CH4 in air using a gas hourly space velocity of 8000 mL gcat.−1 h−1. In contrast, the non-TiO2-doped SCS catalyst is almost inactive at 700 °C whereas it can achieve reactivity (∼24% CH4 conversion and ∼74% C2-C3 selectivity) comparable to the TiO2-doped one at 800 °C. XRD and Raman results evidently reveal that the formation of MnTiO3 during the OCM process appears to be important for the low-temperature OCM activity improvement by TiO2-doping.

A foam-structured Ag-CuOx nanocomposite catalyst obtained by sequential galvanic-deposition of 0.4 wt% Ag and 28 wt% Cu onto a Ni-foam, is highly active, selective and stable for the gas-phase hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG). The best catalyst 0.4-Ag-28-CuOx/Ni-foam was capable of converting more than 96% DMO into MG with a high selectivity of more than 96% and was stable for at least 200 h at 210 °C and a WLHSVDMO of 0.25 h− 1 for a feed of 13 wt% DMO dissolved in MeOH. Silver is responsible to apportion the proportion of Cu+ and Cu0 to an appropriate scale of optimal potency for converting DMO-to-MG.

An FeCrAl-fiber-structured NiO-MgO-Al2O3 nanocomposite catalyst engineered from nano- to macro-scale in one-step is developed via thermally decomposing NiMgAl layered double hydroxides (LDHs) that can be grown onto the FeCrAl-fiber only through a γ-Al2O3/water interface-assisted method. By taking advantages of homogeneous component-distribution in the LDHs-derived NiO-MgO-Al2O3 nanocomposites and enhanced heat transfer, this promising catalyst delivers satisfying performance with enhanced coking/sintering resistance in the title reaction. At 800 °C and a gas hourly space velocity of 5000 mL g–1 h–1, CH4/CO2 conversion maintains almost constant at 91%/89% within the initial 90 h and then slides in a smooth downturn (to 80/85%) within another 180 h of reaction.

IEEE 802.11 wireless LAN is proliferating since the increased trend in the wireless network utilization on mobile devices. Accuracy, fast content delivery, and reliable mobility support are essential features of any network to support the changing trend in a wireless network. However, traditional architectures in wireless LAN (WLANs or WiFi) always endured from challenges such as the provision of consistent mobility, real-time packet flow, and seamless handoff. Generally, most of the WLAN only relies on signal strength for handoff which is not sufficient enough for fair selection of an access point (AP) and therefore causes imperfect performance of the network. We present a novel mobility management scheme for WLANs to deal with the mobility management issues, and load balancing by software-defined network (SDN) and network function virtualization (NFV) technologies. The proposed scheme is based on logical AP (LAP) that keeps a connection with the user/mobile terminal (MT) during handoff triggered by either the user or the SDN controller for seamless mobility. It also involves the current state of each AP in addition to traditional parameters of WLAN. We implemented the proposed scheme on a real testbed in a WLAN environment. The evaluation results authenticate that our proposed scheme provides robust handover without throughput degradation and load imbalance among adjacent APs, and allocates the best AP in the neighboring region. Moreover, our proposed scheme is feasible to implement since it did not require any modification at the mobile terminal.

A high-performance SiC-foam-structured nanocomposite catalyst of CoO@Cu2 O (i.e., 50-100 nm CoO partially covered with ca. 10 nm Cu2 O) was engineered from nano- to macro-scales in one step for the high-throughput gas-phase aerobic oxidation of bioethanol to acetaldehyde. This special CoO@Cu2 O nanostructure shows much higher activity/selectivity than other binary metal-oxide assemblies such as CuOx &CoO nano-mixtures or inverse Cu2 O@CoO nanostructures. The catalyst was facilely but exclusively obtainable by in situ reaction-induced transformation of the respective metal nitrates supported on SiC-foam into the CoO@Cu2 O nanostructure in the reaction stream. It achieved 95 % conversion with 98 % selectivity under mild conditions and was stable for at least 150 h for a feed of 20 vol % ethanol (much higher than in the literature: 1-6 vol %) at a high EtOH weight hourly space velocity of 8.5 h-1 . Abundant Cu2 O-CoO interfaces and high stability of the CoO@Cu2 O nanostructure were responsible for the high activity/selectivity and promising stability in this reaction.

Free-standing stainless-steel (SS)-fiber@meso-HZSM-5 core–shell catalysts engineered from micro- to macro-scale were highly efficiently synthesized via cost-effective steam-assisted crystallization (SAC) method. Impact of synthesis conditions on their morphology and textural/acidic properties was investigated by means of XRD, SEM, TEM, solid-state NMR, NH3-TPD, Py-IR and N2 physisorption. Single-run lifetime of such structured catalysts for MTP process was strongly dependent on their preparation conditions but slightly the product distribution. A volcano-like relationship for lifetime was observed against the SAC time, which was correlated well with the crystallization-time-dependent crystallinity, mesoporosity and crystal size. The promising SS-fiber@meso-HZSM-5 was the one obtained after the SAC for 12 h, which delivered a prolonged single-run lifetime of 620 h with a high propylene selectivity of ∼42% at 450 °C using a methanol weight hourly space velocity (WHSV) of 1 h–1, as the result of high crystal...

The inflexible management and operation of today's wireless access networks cannot meet the increasingly growing specific requirements, such as high mobility and throughput, service differentiation, and high-level programmability. In this paper, we put forward a novel multipath-transmission supported software-defined wireless network architecture (MP-SDWN), with the aim of achieving seamless handover, throughput enhancement, and flow-level wireless transmission control as well as programmable interfaces. In particular, this research addresses the following issues: 1) for high mobility and throughput, multi-connection virtual access point is proposed to enable multiple transmission paths simultaneously over a set of access points for users and 2) wireless flow transmission rules and programmable interfaces are implemented into mac80211 subsystem to enable service differentiation and flow-level wireless transmission control. Moreover, the efficiency and flexibility of MP-SDWN are demonstrated in the performance evaluations conducted on a 802.11 based-testbed, and the experimental results show that compared to regular WiFi, our proposed MP-SDWN architecture achieves seamless handover and multifold throughput improvement, and supports flow-level wireless transmission control for different applications.

A thin-felt, microfibrous-structured Ni@SiO2/Al2O3/FeCrAl-fiber catalyst was fabricated by one-step, top-down macro–micro–nano organization with the aid of cross-linking molecules followed by a calcination treatment. This catalyst is active, selective and stable for the strongly endothermic dry reforming of methane (DRM), as the result of its enhanced resistance to coke and Ni sintering arising from its core–shell-like nanostructure. Notably, no sign of catalyst deactivation is observed, with almost no carbon deposition even after 500 h testing at 800 °C and a gas hourly space velocity of 5000 mL g−1 h−1.

Ni-foam-structured CeO 2 -NiO-Al 2 O 3 catalysts to be used for oxidative dehydrogenation of ethane to ethylene (ODE) have been developed, via chemically etching a Ni-foam followed by CeO 2 modification. The CeO 2 -NiO-Al 2 O 3 /Ni-foam catalysts are highly active and selective with promising stability. With the increase in CeO 2 loading up to 10 wt%, ethane conversion is increased monotonously while ethylene selectivity shows volcano-shaped evolution and reaches its maxima at 7 wt% CeO 2 loading. A high ethylene productivity of 425 g Ethylene kg cat − 1 h − 1 is achieved for a feed gas of C 2 H 6 /O 2 /N 2 = 1/1/8 at 450 °C and a gas hourly space velocity of 18,000 cm 3 g − 1 h − 1 . Promotion effect of CeO 2 additive is also discussed.

The catalytic oxy-methane reforming (COMR) is an effective and effcient route to produce syngas, but the commonly-used Ni catalysts suffer from coke deposition, Ni-sintering and heat transfer limitation. A Ni-foam-structured NiO-MgO-Al2O3 nanocomposite catalyst was developed via thermal decomposition of NiMgAl layered double hydroxides (LDHs) in situ hydrothermally grown onto the Ni-foam. Originated from the lattice orientation effect and topotactic decomposition of LDHs precursor, NiO, MgO and Al2O3 are highly distributed in the nanocomposites, and thus this catalyst delivered enhanced coke-/sintering-resistance. At 700 oC and a gas hourly space velocity of 100 L g-1 h-1, 86.5% methane conversion and 91.8%/88.0% selectivities to H2/CO could be achieved with a stability for at least 200 h. We anticipate that our approach opens a new opportunity for new-generate structured catalytic reactor for COMR process even other high-throughput and/or exothermic reaction processes.

Pd-catalyzed CO coupling to dimethyl oxalate (DMO) process has been commercialized but its reaction mechanism is still open for debate between COCOOCH3∗ and COOCH3∗ (∗, a surface site). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies were performed to clarify such controversy on a high-performance Al-fiber@ns-AlOOH@Pd catalyst. Intermediate species consisting of stretching vibrations of CO and CO, and rocking vibration of CH3 was indeed captured, which could be assigned to either COCOOCH3∗ or COOCH3∗. To make discrimination between COCOOCH3∗ and COOCH3∗, methyl oxalyl chloride (CH3OCOCOCl) and methyl chloroformate (CH3OCOCl) were employed to form COCOOCH3∗ and COOCH3∗ species on the catalyst surface for DRIFTS analyses. Interestingly, the characteristic bands of the as-observed intermediate species in the real reaction matched the obtained COCOOCH3∗ species from dissociative adsorption of CH3OCOCOCl. A double carbonylation reaction pathway was thus confirmed for the CO coupling to DMO, i.e., consecutive insertion of two CO molecules into OCH3∗ to form COCOOCH3∗ followed by combining OCH3∗ to yield DMO (CH3OCOCOOCH3).

Methyl glycolate (MG) is a versatile platform molecule to produce numerous important chemicals and materials, especially new-generation biocompatible and biodegradable poly(glycolic acid). In principle, it can be massively produced from syngas (CO + H

The Ni/SAPO-11 bifunctional catalyst for hydroisomerization of n-hexane was prepared via a novel synthesis method. It involved grinding of nickel source with amorphous precursors used for SAPO-11 followed by crystallization at 473 K for 24 h, thus avoiding the use of extra solvents in the synthesis. The highly dispersed nickel species and acid sites in the Ni/SAPO-11 bifunctional catalyst were instantaneously formed. The Ni/SAPO-11 catalyst contains framework nickel, nickel monoxide (NiO) and nickel aluminate spinel. The nickel monoxide with a size of 2–4 nm provides (de)hydrogenation function after reduction, while the framework nickel supplies more acid sites leading to an enhanced isomerization activity. The Ni/SAPO-11 catalyst shows a great synergetic effect between the metallic nickel and acid sites with a high metal-to-acid sites ratio (CNi/CA) and close proximity. A single metallic nickel site is able to balance ca. 5 acid sites (CNi/CA ≈ 0.19) over the Ni/SAPO-11 catalyst in n-hexane hydroisomerization. The high dispersion of nickel over the catalyst provides relatively excessive metal sites (CNi/CA > 0.19), leaving the rate limiting reaction to occur on the acid sites. The Ni/SAPO-11 catalyst exhibits comparable n-hexane conversion (71.2%) and iso-hexane yield (66.7%) to the classical Pt/SAPO-11 catalyst. With enhancing acidity, the Ni/SAPO-11 catalyst exhibits one of the highest iso-hexane yields reported in the n-hexane hydroisomerization, which render the new material as a promising candidate for the hydroisomerization catalysts.

Summary CO2 circular economy is urgently calling for the effective large-scale CO2 reutilization technologies. The reverse water-gas shift (RWGS) reaction is the most techno-economically viable candidate for dealing with massive-volume CO2 via downstream mature Fischer-Tropsch and methanol syntheses, but the desired groundbreaking catalyst represents a grand challenge. Here, we report the discovery of a nano-intermetallic InNi3C0.5 catalyst, for example, being particularly active, selective, and stable for the RWGS reaction. The InNi3C0.5(111) surface is dominantly exposed and gifted with dual active sites (3Ni-In and 3Ni-C), which in synergy efficiently dissociate CO2 into CO* (on 3Ni-C) and O* (on 3Ni-In). O* can facilely react with 3Ni-C-offered H* to form H2O. Interestingly, CO* is mainly desorbed at and above 400°C, whereas alternatively hydrogenated to CH3OH highly selectively below 300°C. Moreover, this nano-intermetallic can also fully hydrogenate CO-derived dimethyl oxalate to ethylene glycol (commodity chemical) with high selectivity (above 96%) and favorable stability., Graphical Abstract, Highlights • InNi3C0.5 catalyst is highly active, selective, and stable for the RWGS reaction • InNi3C0.5(111) surface is gifted with dual active sites (3Ni-In and 3Ni-C) • CO2 is dissociated into CO* (preferentially desorbed) on 3Ni-C and O* on 3Ni-In • InNi3C0.5 is also promising for application in carbonyl-to-hydroxyl processes, Chemical Reaction; Catalysis; Nanomaterials

As the sensor layer of Internet of Things (IOT), enormous amount of sensor nodes are densely deployed in a hostile environment to monitor and sense the changes in the physical space. Since sensor nodes are driven with limited power batteries, it is very difficult and expensive for wireless sensor networks (WSNs) to extend network lifetime. In order to achieve reliable data transmission in WSNs, energy efficient routing protocol is a crucial issue in extending the network lifetime of a network. However, traditional routing protocols usually propagate throughout the whole network to discover a reliable route or employ some cluster heads to undertake data transmission for other nodes, which both require large amount energy consumption. In this paper, to maximize the network lifetime of the WSN, we propose a novel energy efficient region source routing protocol (referred to ER-SR). In ER-SR, a distributed energy region algorithm is proposed to select the nodes with high residual energy in the network as source routing node dynamically. Then, the source routing nodes calculate the optimal source routing path for each common node, which enables partial nodes to participate in the routing process and balances the energy consumption of sensor nodes. Furthermore, to minimize the energy consumption of data transmission, we propose an effective distance-based ant colony optimization algorithm to search the global optimal transmission path for each node. Simulation results demonstrate that ER-SR exhibits higher energy efficiency, and has moderate performance improvements on network lifetime, packet delivery ratio, and delivery delay, compared with other routing protocols in WSNs.

In the past years, the issues of energy efficiency and interference are becoming increasingly serious in wireless local area network (WLAN) since lots of access points (AP) are deployed densely to provide high-speed users access. However, current works focus on solving the two issues separately and the influence of each other is rarely considered. To address these problems, we propose a joint optimization scheme of energy efficiency and interference to reduce energy consumption and interference together without sacrificing users’ traffic demands. Firstly, based on energy consumption measurement of AP and network interference analysis, we establish energy efficiency and interference models respectively. Then, the weighting method is introduced to build the joint optimization to quantify the effects of user-AP association, AP switch, AP transmit power and AP channel on energy consumption and interference. Lastly, we formulate the joint optimization as an Mixed Integer Non-Linear Programming (MINLP) problem. Since the MINLP problem is NP-hard, we proposed an Joint Optimization of Energy Efficiency and Interference (JOEI) algorithm based on greedy method to simplify its computational complexity. The evaluation results show that the proposed algorithm can effectively reduce the network energy consumption while improve the capacity of WLANs.

© 2019 John Wiley & Sons, Ltd. The high-bandwidth demands from variety of applications drive a dense wireless local access network (WLAN), which results in a complicated wireless network scene with serious co-channel interference and energy waste. In this paper, to reveal the interactions between interference and energy efficiency, we propose an interference-energy efficiency (IFEE) model to quantify the interference impact on the energy efficiency of 802.11 access point (AP) devices. Firstly, we introduce the channel separation and the difference of received signal strength indication (D-RSSI) as two indicators to extend the classical signal to interference plus noise ratio (SINR) notion and rate adaptive mechanism. Then, these two parameters are integrated into the energy consumption model to establish the IFEE model. Lastly, we conduct extensive measurements with five typical WiFi interference scene in real network to validate the effectiveness of our model. The comparisons between simulation results and real data demonstrate that the proposed IFEE model can quantify the interference and energy efficiency with high accuracy, which can be used for wireless network optimization and protocol design.

Combined with the analysis of FT-IR, lignite was treated by conventional flue gas (FTD), hydrothermal (HTD), and tetralin solvent thermal pretreatment (TTD) at different temperatures. A series of infrared parameters were obtained, and the evolution of chemical structure and hydrocarbon generation potential for lignite were studied. The results showed that the HTD, TTD and FTD processes reduce the water holding ability of lignite, and in general, the order of the dewatering effect is HTD > TTD > FTD. The FTD process promotes more efficient the increase of carbon content and energy density, and the upgraded coal likely to be suitable as power fuel. For lignite, the hydrogen-enrichment parameters are not an effective means to predict hydrocarbon generation potential, because the structural characteristics are not dominant during the process of hydrocarbon generation. The aromatization occurred during the FTD, HTD, and TTD processes, and has an important contribution towards enhancing the aromaticity. The order of aromatization of lignite for the three pretreatment processes is FTD > HTD > TTD. Conversely, the upgraded coal achieved by TTD process maintains the relative integrity of organic structure and high reactivity of lignite. HTD and TTD processes improve the H/C atom ratio of lignite, which provides more hydrogen free radicals to produce chemical products. Thus, the upgraded coal is suitable as feedstock of coal pyrolysis and liquefaction. Moreover, the upgraded coal achieved by TTD process retains high reactivity and relative integrity of organic structure compared with the HTD process. Thus, it has a much better chance of producing value-added chemical products.

Deep dry screening is the key unit in mineral processing. A vibrating flip-flow screen (VFFS) with elastic sieve mats has been widely used for screening fine-grained minerals due to its good performance. The stability of the VFFŚs dynamic response largely affects its screening efficiency and processing capacity, however, it has rarely been investigated in detail. In this paper, aiming at reducing the effect of loading-material for dynamic system through properly operated parameters, stability regions were defined, and for the given working conditions, using performance criteria to evaluate the vibration stability. This was done by theoretical modeling and experimental analysis for the VFFS system. The VFFS can operate in different regions by regulating the shear spring characteristics and the eccentric mass moment. The dynamic response curves were measured and analyzed under different operating conditions; and then, material-loading experiments were carried out to verify the stability of VFFS; furthermore, the method of multistage sampling and multilayer was used to analyze the screening performance of material under three conditions. Results indicated that loading material on VFFS affected its vibration stability and therefore the screening performance. The dynamic response of VFFS was more stable in the near anti-resonance region (a certain distance to the left of anti-resonance frequency) than the other two operating conditions, thus, was not obviously affected by loading material. Screening efficiency for 3 mm material was up to 89.05% with a corresponding total misplaced material of 7.96%.

A monolithic silicon carbide foam (SiC-foam) structured nickel and lanthanum oxide (Ni-La2O3) nanocomposite catalyst is developed via reducing the nickel oxide and lanthanum oxide (NiO-La2O3) precursor that can be grown onto SiC-foam surface by depositing the needed citric acid gel followed by calcination at 750 °C. By taking the advantages of homogeneous component-distribution and strong Ni-La2O3 interactions in the Ni-La2O3 nanocomposites, this catalyst delivers much enhanced coke-depositing/Ni-sintering resistance than the unmodified counterpart of Ni-La2O3/alumina (Al2O3) in the titled reaction. At 850 °C, a weight hourly space velocity (WSHV) is set as 24,000 mLCH4-CO2 gCat−1 h−1, methane/carbon dioxide (CH4/CO2) conversions of 71/85% are initially achieved on the Ni-La2O3/SiC-foam catalyst followed by progressively decreased to 60/72% within 50 h (h), but remain almost unchanged for the next 50 h. On the contrary, the CH4/CO2 conversions on the Ni-La2O3/Al2O3 catalyst rapidly drop from 49/71% to 24/40% within only 25 h due to its serious Ni-sintering and coke deposition.

A Ni-foam-structured PdNi nanoalloy catalyst engineered from nano- to macro-scales has been successfully fabricated for the catalytic deoxygenation of coalbed methane (CBM). The catalyst was obtainable by embedment of Pd nanoparticles onto Ni-foam substrate via a galvanic exchange reaction method and subsequent in situ activation in the reaction, which was active at low temperature, selective (no CO formation), and oscillation free in this CH4-rich catalytic combustion process. Special Pd@NiO (Pd nanoparticles partially wrapped by tiny NiO fragments) ensembles were formed in the galvanic deposition stage and could merely be transformed into PdNi nanoalloys in the real reaction stream at elevated temperatures (e.g., 450 °C or higher). Density functional theory (DFT) calculations were carried out to reveal the role of Ni decoration at Pd in PdNi nanoalloy catalyst for the CBM deoxygenation. By nature, the Pd–Ni alloying modified the electronic structure of surface Pd and led to a decrease in the O adsorptio...

A high-performance PdNi(alloy)/Ni-foam catalyst to be used for coalbed methane (CBM) deoxygenation via catalytic combustion was developed with the aid of galvanic deposition of Pd nanoparticles onto the monolithic Ni-foam followed by in-situ reaction-induced Pd-Ni alloying. The investigations concerning the preparation/reaction conditions and heat/mass transfer indicated that such PdNi(alloy)/Ni-foam catalyst provided a unique combination of high low-temperature activity/selectivity, oscillation-free, high permeability and enhanced heat transfer. As an example, the catalyst with a low Pd-loading of 1 wt% could deliver a complete O 2 conversion for a simulated feed of CH 4 /O 2 /N 2 (40/3/57, vol%) at 350 °C with a high gas hourly space velocity of 12,000 mL g cat. −1 h −1 , and particularly, this catalyst was stable for at least 500 h without deactivation and reaction oscillation. In-situ reaction-induced Pd-Ni alloying was clearly revealed and by nature was responsible for the low-temperature activity (expressed by turnover frequency) promotion and oscillation suppression. The underlying mechanism for CBM deoxygenation over the PdNi(alloy)/Ni-foam catalyst is proposed to be a Langmuir-Hinshelwood type.

Thin-sheet microfibrous-structured Al-fiber@ns-AlOOH@Pd catalysts with low Pd-loading engineered from micro- to macro-scale are developed for the gas-phase CO coupling to dimethyl oxalate, providing unique combination of high activity/selectivity and good stability with high permeability and high thermal conductivity. The support of Al-fiber@ns-AlOOH is initially prepared via endogenous growth of boehmite nanosheets (ns-AlOOH) on 3D network of 60-μm Al-fiber. The palladium is then placed onto the surface of the ns-AlOOH rooted on the Al-fiber via incipient wetness impregnation method with a toluene solution of palladium acetate. As an example, the catalyst with a low Pd-loading of 0.25 wt% delivers ∼66% CO conversion and ∼94% DMO selectivity for a feed of CH 3 ONO/CO/N 2 (10/14/76, vol%) with a gas hourly space velocity of 3000 L kg −1 h −1 , and particularly, is stable for at least 200 h without deactivation. Our Al-fiber@ns-AlOOH@Pd catalyst demonstrates two times higher intrinsic activity (expressed by turnover frequency) compared to a traditional Pd/α-Al 2 O 3 . The existence of Pd-hydroxyl synergistic interaction is paramount to the enhanced catalytic performance for the CO coupling reaction, by nature, as the result of hydroxyl-promoted adsorption of bridged CO on the Pd surface.

Free-standing NiO–MgO composite nanosheet catalysts to be used for catalytic oxy-methane reforming (COMR) have been developed by in-situ growing onto the Ni-foam struts under hydrothermal condition followed by calcination treatment. Among them, the NiO–MgO/Ni-foam consisting of 1.0% MgO, 18.7% NiO and nickel-foam-strut balance is the best structured catalyst engineered from nano- to macro-scale, being capable of converting 82.9% CH4 into syngas at selectivity of 94.7% to H2 and of 89.9% to CO for a feed of CH4/O2=2/1 (vol/vol), at 700 °C and a high gas hourly space velocity of 100 L g−1 h−1. Nevertheless, improvement of their carbon resistance and textural stability is particularly desirable.

For the methanol-to-propylene process, a lumped kinetic model was developed on the basis of dual-cycle reaction mechanism, which attempted to reflect the main reaction paths with a combination to show the evolution of mole fraction of individual light olefins ( C 2 , C 3 and C 4 ) with space time. The experiments were performed in a continuous flow fixed-bed reactor at 0.1 MPa as well as varied reaction temperature from 400 to 480 °C and space time from 0.3 to 32.0 gcatalyst h mol−1, and the experimental data obtained on the structured SS-fiber@HZSM-5 and powdered HZSM-5 catalysts were fitted by MATLAB software based on the established model. The fitted results show that the lumped kinetic model well describes the product distribution and is identified to be suitable by model identification. Compared to the powdered HZSM-5, the SS-fiber@HZSM-5 shows higher diffusion efficiency and narrower residence time distribution, not only promoting the propylene formation but also improving the utilization efficiency of the structured HZSM-5.

Structured Pd–Au–CuOx/Cu-fiber obtainable by a galvanic co-deposition method is post-modified by La2O3 and consequently shows promising low-temperature activity and stability for the titled reaction, due to the in situ formation of a La2O3–PdAu(alloy)–Cu nanocomposite in the reaction thereby leading to enhanced ability for H2 activation and H-spillover associated with the La2O3-assisted activation of CO and C–O groups of dimethyl oxalate.

Promising microfibrous-structured Al-fiber@ns-Al2O3@Fe–Mn–K catalysts are developed for the mass/heat-transfer limited Fischer–Tropsch synthesis of light olefins. The Al-fiber@ns-Al2O3 core–shell composites, engineered on the nano- to macro-scale, are first prepared by endogenously growing thin shell (∼0.5 μm) nanosheet γ-Al2O3 (ns-Al2O3) onto the 3-dimentional microfibrous-structured network consisting of 10 vol% 60 μm Al-fiber and 90 vol% voidage. After modification by K through an impregnation method, the Al-fiber@ns-Al2O3 composites are functionalized with nano-structured Fe and Mn active components via a surface impregnation combustion method. The effect of combustion atmospheres (air, N2, and N2 followed by air (N2–air)) on the catalyst performance is investigated. The as-burnt catalyst obtained under air delivers the highest iron time yield of 206.0 μmolCO gFe−1 s−1 at 89.6% CO conversion with 42.1%C selectivity to C2–C4 olefins (350 °C, 4.0 MPa, 10 000 mL (g−1 h−1)), while the other two as-burnt catalysts under N2 and N2–air yield relatively low CO conversions of 58–67%. Combustion under air is helpful to form 6 nm Fe–Mn–K oxide particles with better reducibility and carbonization properties thereby leading to high performance. In contrast, under either N2 or N2–air atmosphere, smaller oxide particles (3–4 nm) are formed but suffer from deteriorated reducibility and carbonization properties due to the strong support–metal interaction. Such as-burnt catalysts obtained under air also demonstrate promising stability.

A self-supported SS-fiber@meso-HZSM-5 core–shell catalyst was essentially designed and engineered from micro- to macro-scale by caramel-assistant hydrothermal synthesis. The significant role of caramel during the crystallization process was revealed in detail. Caramel not only created the mesoporosity in the ZSM-5 crystals, but also released acid under hydrothermal synthesis conditions which lowered the zeolite crystallinity. By taking advantage of the mesopore development in a hierarchical micro–meso–macropore structure with favourably-tuned acidic properties, such a catalyst provided a dramatically prolonged lifetime of 845 h (>90% conv.) with high propylene selectivity (e.g., 48%) in the MTP reaction. The hierarchical pore structure development mainly increased the accommodation capacity of the zeolite shell for receiving formed coke thereby leading to a dramatically prolonged lifetime in the MTP reaction.

Production of substitute natural gas (SNG) by methanation of syngas generated from various carbon sources provides a promising route towards coal clean utilization and sustainable energy future. Monolithic Ni (or Cu, NiCu-alloy)-foam-structured Ni–Al2O3 catalysts were developed by a facile modified wet chemical etching method. The as-prepared catalysts were characterized by X-ray diffraction, scanning electron microscopy, inductively coupled plasma atomic emission spectrometry and H2-temperature programmed reduction. Among these catalysts, Ni–Al2O3/Ni-foam has the most surface active Ni atoms and exhibits the best catalytic methanation performance, achieving 99.9% CO conversion with 90.0% methane selectivity and being stable for at least 1000 h for a feed gas of H2/CO (3/1) at 330 °C and gas hourly space velocity (GHSV) of 5000 h−1. Effects of reaction temperature, reaction pressure and GHSV are also investigated on the catalytic performance of Ni–Al2O3/Ni-foam for CO methanation. Computational fluid dynamics calculation and experimental measurement consistently show that such monolithic Ni–Al2O3/Ni-foam can dramatically reduce the “hotspot” temperature due to its high thermal conductivity. Moreover, the feasibility of our Ni–Al2O3/Ni-foam catalyst for co-methanation of a simulated feed gas from coal gasification is studied as well as CO2 methanation in the presence of high CH4 concentration. We anticipate that our present work might stimulate commercial exploitation of the new-generation structured catalyst and reactor technology for the strongly exothermic syngas methanation toward energy-efficient process for SNG production.

Catalytic distillation (CD) offers a unique integration of distillation and catalysis to selectively separate products in situ while making a positive shift of chemical equilibrium and has therefore been well received as an inviting avenue to green chemical processing. Rendering novel structured catalytic packings is particularly desirable but remains challenging. Herein, we present a microfibrous-structured Nafion–SiO2/SS-fiber solid acid catalyst and demonstrate its separation and reaction efficiency as CD packings for esterification to produce ethyl acetate from acetic acid and ethanol. A thin-sheet microfibrous structure with 15 vol% 20 μm stainless steel fibers (SS-fiber) and 85 vol% void volume was shaped into θ-ring analogues. Nafion was then firmly locked into the SiO2 layer that was anchored onto the SS-fiber surface by a dip-coating method using self-crosslinking Nafion–SiO2 sol–gel prepared by Nafion-catalyzed hydrolysis of tetraethylorthosilicate (TEOS). Such micro-structured Nafion catalysts worked effectively and efficiently in the CD for esterification of acetic acid with ethanol as the result of a unique combination of high catalyst performance (stability, adequate acidic sites and high mass/heat transfer) and instantaneous distillation. For instance, high total (93.6%) and actual (91.6%) yields of ethyl acetate with 96.2% purity were achievable at a high space-time yield (4.3 g mmol−1 h−1) while the high CD efficiency was maintained for 40 h over 5 consecutive batch runs.

Monolithic microstructured Al-fiber@HZSM-5 core-shell catalysts have been synthesized by directly growing the shell of HZSM-5 with varied SiO 2 /Al 2 O 3 molar ratio on the core of sinter-locked aluminum microfibers. Such monolithic catalysts are examined in the methanol-to-propylene reaction, and the best microstructured catalyst of HZSM-5 with SiO 2 /Al 2 O 3 molar ratio of 200 delivers a C 2 –C 4 selectivity of 62% (~ 36% to C 3 ) as well as a single-run lifetime of 160 h under industrial relevant conditions.