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An updated H2/O2 kinetic mechanism was proposed by incorporating carefully selected reaction rate coefficient and great progress in radical chain mechanisms, in which the uncertainties of rate coefficient were discussed. The performance of the current mechanism was compared to other H2 mechanism and validated against a wide range kinetic targets, including oxidation, decomposition in shock waves, ignition, flame speed and flame structure. Results show that the current mechanism obtains an overall improvement of performance, especially for the flame speed. By using the updated binary diffusion coefficient from ab initio calculations and the chemically termolecular reactions, the current mechanism presents better agreement with the new experimental flame speed at atmospheric pressure and obtains the improved performance with respect to the negative pressure dependence of high-pressure H2 flame. Furthermore, the flame speed predictions are strongly sensitive to the H2O third body efficiency in the H2 mechanism, affecting the water-contained H2 flame. The modeling results of rapid compression machine ignition show that present mechanism can more accurately predicts the ignition delay under engine-like conditions. However, all three mechanisms cannot accurately reproduce the negative pressure dependence behavior of mass burning rate in high-pressure H2 flame, which may be attributed to the fact that the important reaction O + OH(+M) = HO2(+M) that significantly affects lean high-pressure H2 flame is not included in current mechanism. Consequently, continuous works should be emphasized on the reactions that are important but neglected in H2 mechanism. All these not only develop an improved H2 reaction mechanism for high-pressure combustion, but also point out the direction for refining the H2 mechanism.

The respective performances of hypothetical Stirling engine and Stirling cooler in Vuilleumier machines are usually unclear. In this paper, a method of alternate combination of adiabatic sub-model with considering the losses and isothermal sub-model without considering the losses was proposed. The engine's work output is obtained by combining adiabatic engine and isothermal cooler, while the cooler's work input is obtained by combining adiabatic cooler and isothermal engine. Then, engine's thermal efficiency and cooler's coefficient of performance (COP) were obtained. The relative Carnot efficiency of hypothetical engine was 45%–57% at conditions of 550 °C hot temperature and 50 °C–70 °C warm temperature. The relative Carnot efficiency of hypothetical cooler was 44%–51% at conditions of −20 °C~10 °C cold temperature and 50 °C~70 °C warm temperature. In addition, a comparison of Vuilleumier machines’ COP based on a complete adiabatic model and the hybrid model was made. The ratio of COPV,hybrid over COPV,adia was in the range of 0.9~0.94. It indicated that the respective thermal efficiency and COPcooler in the hybrid model could approach to those in a complete adiabatic model.

The methane oxy-fuel combustion highly diluted by CO2 at supercritical region has the best potential for its near-zero emission characteristics and high thermal efficiency, while its auto-ignition characteristic is still not clear. In current investigation, a model with detailed chemical kinetic mechanism was introduced to research its ignition delay times (IDs). Results showed that the fold points in low-temperature and high-pressure region is due to CH3O2 which only involved in Aramco-Mech 1.3. When temperature increases, the inhibition of the termination reactions plays a dominate role at low pressure, while the promotion of the branching reactions contributes more to the acceleration of ignition at high pressure. Five dominant pathways and their variations were clarified to depict the inhibition effect of the ratio of CO2/O2. Based on the newly proposed combustion mode, it was found that temperature dependence of the nonnegligible CO2 collision effect is opposite under low and high pressure with full-oxy combustion mode. This investigation extended the research region to higher pressure and comprehensively studied the relevant factors on the auto-ignition which not only provides theoretical reference for the chemical kinetics study of methane, but also contributes to the further researches of EGR, SCF and near-zero emissions technologies.

Water direct injection into the cylinder is one of effective ways to suppress the combustion rate and knocking combustion in turbocharged SI engine. In this study, a detailed one-dimensional model coupled with the water direct injection was built by using the GT-Power according to the real tested hydrogen-enriched lean-burn natural gas (NG) SI engine, and validated against the experimental data. Then, a series of cases with various water injection quantity and injection timing were comprehensively investigated on the thermodynamics, combustion and emissions characteristics of the NGSI engine. The impact of the thermo-physical of the water were discussed in detailed by sweeping various water injection quantity and water injection timing. The results indicated that peak combustion pressure and peak heat release rate decreased with the increasing the water injection quantity. In addition, the 50% combustion location and peak combustion pressure location were retarded with the increasing the water injection quantity. As for the water injection timing, the peak combustion pressure and peak combustion temperature were slightly decreased with retarding the water injection timing. Apart from that, the indicated thermal efficiency decreased 4.03% and the equivalent fuel consumption increased 3.56% with injecting 60 mg water into the cylinder compared the case without water injection. Furthermore, the indicated thermal efficiency decreased 4.68% and the equivalent fuel consumption increased 4.66% by sweeping the water injection timing from the 150 CA to 50 CA before top dead center. However, the volumetric efficiency slightly ascended with increasing the water injection quantity and retarding the water injection timing. Finally, the NOx emissions declined with increasing the water injection quantity and retarding the water injection timing. However, CO emission and unburned HC emissions increased with increasing the water injection quantity and retarding the water injection timing. The main aim of this paper is expected to provide a comprehensively assessment of the thermo-physical of water on the thermodynamics, combustion, and emissions of the hydrogen enriched NGSI engine.

In this paper, three recently updated mechanisms were compared with experimental data, and FFCM 1.0 mechanism was chosen to perform chemical kinetic investigation of laminar burning velocity (LBV) for CH4/H2 mixtures. Results show that increasing hydrogen and pressure, LBV presents opposite results, which depends on the competition between promotion and inhibition effect at different hydrogen fractions and pressures. Based on growth rate of LBV, it is possible to determine three regimes for CH4/H2 mixtures at high pressures. When hydrogen fraction is less than 60%, the LBV of CH4/H2 mixtures at high pressures is not very sensitive to hydrogen, showing complex variation. Flame structure and radical concentration imply that the enhanced LBV by adding hydrogen, which is a combined result of chemical and thermal effects, is realized by improving the active radical production. Then, quantitative analysis of contribution value found that reaction OH+H2=H+H2O plays an important role in H production with increasing hydrogen fraction at high pressure. Through this work, it not only studied the interactive effect between CH4/H2 combustion system and varied conditions (such as pressure and hydrogen fraction), but also the influence mechanism was revealed in depth. All these have provided useful suggestions on fuel design for power machines.

The Coefficient of Performance of Vuilleumier cycle with ideal reversible changes is much higher than those obtained in practical machines. In this paper, an analytical model based on Hofbauer's Vuilleumier cycle (HVC) had been developed. The expansion and compression processes in the model were adiabatic. The expansion volume ratios for HVC were defined and formulas for determination of expansion volume ratios were derived. As the HVC is essentially consisted of hypothetical Stirling engine cycle and Stirling cooler cycle, the respective analytical models for Stirling engine cycle and Stirling cooler cycle were investigated firstly. The effects of regenerator effectiveness and expansion volume ratio were obtained. Then, the expansion volume ratios in the HVC were investigated and obtained at various ratios of dead volumes and temperatures. Then, the performance of HVC at various expansion volume ratios were obtained. Furthermore, the expansion volume ratios in a practical HVC machine was investigated. It was in the range of 1.045–1.068 for Stirling engine cycle and 1.091–1.095 for Stirling cooler cycle. The results showed that the performance could be improved by lifting the expansion volume ratios.

The ever-mounting drilling operations in the petroleum industry has been accompanied by a tremendous amount of wasted drilling fluid, Polycyclic Aromatic Hydrocarbons (PAHs) in which pose a huge th...

Ischemia-reperfusion (I/R)-induced organ injury is a serious health problem worldwide, and poor recovery of acute phase injury leads to chronic fibrosis and further organ dysfunction. Thus, a more precise approach to enhance tissue repair is needed. By using a renal I/R model, we aimed to evaluate the role of a hydrogel-based dual-drug delivery platform on promoting tissue repair. An injectable, self-assembling peptide/heparin (SAP/Hep) hydrogel was used to co-deliver TNF-α neutralizing antibody (anti-TNF-α) and hepatocyte growth factor (HGF). The microstructure and controlled release properties of KLD2R/Hep hydrogel were analyzed. The effects of the drug-loaded hydrogel (SAP-drug) on renal injury were evaluated in mice with I/R injury. In vitro, the SAP/Hep hydrogel allowed for a faster release of anti-TNF-α with a sustained release of HGF, and both drugs maintained their bioactivities after release. In vivo, combined anti-TNF-α/HGF showed better renal protective potential than anti-TNF-α or HGF alone. SAP-drug (anti-TNF-α/HGF in SAP hydrogel) treatment reduced the level of serum creatinine (Scr), blood urea nitrogen (BUN), tubular apoptosis, renal inflammatory factors, and macrophage infiltration compared to Free-drug (anti-TNF-α/HGF in solution) or SAP alone. Moreover, the SAP-drug group had better efficacy on promoting tubular cell proliferation and dedifferentiation than SAP or Free-drug alone, and thus reduced chronic renal fibrosis in I/R mice. This study highlighted that SAP could sequentially deliver the two drugs to achieve anti-inflammatory and pro-proliferative effects with one injection and thus is a promising delivery platform for tissue repair. STATEMENT OF SIGNIFICANCE: Ischemia-reperfusion (I/R)-induced organ injury is a serious health issue, and delayed tissue repair leads to chronic fibrosis and organ failure. Systemic administration of anti-inflammatory agents or growth factors have shown some benefits on I/R injury, but their therapeutic efficacy was limited by side effects, poor bioavailability, and absent key signals of tissue repair. To address these issues, a hydrogel-based drug co-delivery platform was used to treat I/R injury. This platform could achieve sequential release kinetics with faster rate of anti-TNF-ɑ and slower rate of HGF, and effectively promoted tissue repair by targeting inflammation and proliferation in mice with renal I/R. This nanoscale delivery platform represents a promising strategy for solid organs (heart, liver and kidney) regeneration after I/R.

In this research, a newly proposed method combining Chemkin with CONVERGE was used to study the transient in-cylinder chemical reaction process in NG-diesel dual fuel engine. The selected mechanism was verified by comparing the results of CONVERGE with experimental data, and then the calibrated model of CONVERGE was used to provide boundary conditions for Chemkin. On this basis, the detailed combustion process was simulated at different natural gas substitution ratio (NGSR). The results show that, the chain branching reaction, long-chain to short-chain reaction, and reactions associated with OH radicals have significant impacts on temperature. It can also be found that the combustion of fuel shows a distinct two-stage reaction process. During the low temperature stage, both the CO and NO emissions are little. While at the high temperature stage, the CO emissions first rapidly increase and then decrease due to the consumption reaction, and the NO emissions also have a quick increase. When the NGSR is reduced, a new path for CO generation occurs at low temperature stage, resulting in minor increase (up to 0.0019 mol fraction) of CO concentration. Meanwhile, the ignition delay is reduced significantly (by 88.5%), but the increase of diesel species does not alter the formation mechanism of emissions. All these provide guidance for improving combustion and emission performance of NG-diesel dual fuel engine.

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have shown great potential for tissue repair, but their therapeutic capacity is limited by rapid clearance and short half-life. Herein, we purposed a hydrogel-based slow release strategy to enhance the therapeutic potency of EVs. A matrix metalloproteinase-2 (MMP2) sensitive self-assembling peptide (KMP2) hydrogel was used for the local delivery of MSC-EVs. The structure and controlled release properties of the KMP2 hydrogel were analyzed. The effects of the EV-loaded KMP2 hydrogel (KMP2-EVs) on cell apoptosis, inflammation and angiogenesis were evaluated in mice with renal ischemia-reperfusion (I/R) injury. In vitro, KMP2 formed a cross-linked nanofiber hydrogel to encapsulate MSC-EVs. KMP2 showed greater degradation and EV release in response to MMP2. The released EVs had similar structures and bioactivities as fresh, isolated EVs. In vivo, I/R mice treated with KMP2-EVs showed improved renal function by reducing tubular cell apoptosis, pro-inflammatory cytokine expression, and macrophage infiltration than mice receiving either EVs or KMP2. Moreover, KMP2-EVs showed better efficacy on promoting endothelial cell proliferation and angiogenesis than KMP2 or EVs alone, which subsequently decreased chronic renal fibrosis in I/R mice. This study highlighted that the EV-released KMP2 hydrogel is a promising cell-free therapy for tissue repair.

In this study, a detailed 1D simulation model of the hydrogen-enriched natural gas SI engine was built according to realistic engine layout in the lab with practical boundary conditions, and validated against the experimental data. Four different types of EGR systems were comprehensively investigated, including a low-pressure (LP) EGR, a high-pressure (HP) EGR, their combinations, and an internal EGR, using the validated 1D simulation model of the hydrogen-enriched natural gas SI engine for their combustion, performance, and emissions characteristics. The results indicated that the peak combustion pressure of the in-cylinder pressure decreased with increase in EGR ratio either using the HP, LP, or combined HP-LP systems. The NOx emissions with the HP EGR were observed to be lowest of all types of EGR systems. Combined the 10% HP EGR ratio with the 5% LP EGR ratio (total 15% EGR ratio) was predicted to achieve the highest indicated thermal efficiency compared with other EGR strategies. As for the internal EGR, the peak combustion pressure and the heat release rate slightly increased with decrease in the valve overlap. Moreover, the indicated thermal efficiency firstly increased with decrease in overlap and then slightly declined. The internal EGR was mainly determined by the timing of the exhaust valve closing; However, it was not the only influence factor. The positive and negative waves in the intake and exhaust systems also played a crucial role in the gas exchange process and volumetric efficiency.

This paper reports the first use of Tribulus terrestris extract (TTS), a newly developed nonionic surfactant, as an inhibitor for shale hydration. The critical micelle concentration of TTS was dete...

Vuilleumier heat pumps can reduce the consumption of fossil combustion and thus have huge potential for applications in heating systems. However, it receives less attentions. In this paper, a Vuilleumier heat pumps with alternate move-and-stop motions (Hofbauer–Vuilleumier heat pump) was studied. A theoretical adiabatic model and a simple adiabatic model were derived. Both models were compared to the numerical adiabatic model and isothermal model. The results of theoretical adiabatic model agreed well with that of the numerical adiabatic model in terms of Qh, Qc, COP, pressure and temperature. The accuracy of the simple adiabatic model was relatively worse than the theoretical adiabatic model but much higher than the isothermal model. Furthermore, the effects of hot, warm and cold temperatures, initial pressure, dead volumes and various heat losses (regenerators’ heat losses, displacers’ shuttle losses, pumping losses and axial conduction losses) on the performance were investigated.

Water-based drilling fluids are characterized by cost-effective, wide sources of raw materials, and environmental friendliness. However, it is prone to cause various accidents that affect the drill...

Nano-lignosulfonate (Nano-LS) was formed gradually from the inside to outside through the layer by layer self-assembly method under the interaction of π-π bond and synergistic effect of ultrasound. Then acrylamide (AM) and 2-Acrylamido-2-methylpropanesulfonic acid (AMPS) were grafted onto Nano-LS in aqueous solution, potassium persulfate used as initiator. The structure of resulting the graft copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H NMR) methods. Thermogravimetric analysis (TGA) revealed the thermal stability of the graft copolymer and the results showed that the thermal decomposition of the graft copolymer was after 295.16 ℃. The graft copolymers with different additions were prepared in water-based drilling fluids (WBDFs) and the action mechanism of graft copolymer in water-based drilling fluid was revealed by scanning electron microscopy (SEM). The rheological and filtration properties of drilling fluids were evaluated before and after hot rolling (BHR and AHR) at 200.0 ℃ for 16.0 h. The results revealed that the fluid exhibit shear thinning behavior under static conditions as a gelatinous structure. When the amount of graft copolymer is 3.0 wt%, the result showed that the fluid loss (FLAPI) can be significantly reduced to 7.5 mL after hot rolling at 200.0 ℃ for 16.0 h. Moreover, the results showed that the thermal stability, salt resistance and calcium resistance of the graft copolymers are high enough to be used as effective additives in high temperature, high salinity and high calcium water-based drilling fluids.

In the presented study, the influence of lean-burn on combustion and emission performance of diesel pilot ignition natural gas engine was investigated by using the method of computational fluid dynamics coupling with the reduced chemical kinetic model. Based on bench tested results, the computational fluid dynamics model was validated in four typical conditions, and then it was used for the simulation at different excess air coefficient. Due to the visibility of computational fluid dynamics results, the combustion medium process and emissions medium products were obtained, which then were used to explain the influence mechanism of excess air coefficient. The simulated results show that, under 50% load, the maximum cylinder pressure becomes larger and the start of combustion is advanced when the excess air coefficient increases from 1.0 to 1.5, and the maximum advance of the start of combustion reaches 9.5 °CA. Nevertheless, under 100% load, the start of combustion is advanced first and then retarded. Meanwhile, the higher the excess air coefficient is, the earlier the heat release rate shoots up. When the excess air coefficient increases from 1.2, the 10–50%, 50–90% and 10–90% combustion duration become longer. The nitrogen oxide emission increases as the excess air coefficient rises from 1.0 to 1.1 but decreases if it continues to increase. The unburned methane emission decreases first and then increases with the increase of the excess air coefficient. Nevertheless, at 1500 rpm and full load, the unburned methane emission shoots up as the excess air coefficient changes from 1.3 to 1.5 and the maximum difference of unburned methane emission reaches 3233 ppm.

The CuO micro/nanowires film has been prepared successfully on a Cu substrate using a combination of an electrochemical anodization and an annealing treatment. Its morphology and phase composition ...

Water splitting has been considered as one of the most promising strategies for renewable energy production. The process of water electrolysis is greatly influenced by the sluggish kinetics of the oxygen evolution reaction (OER). Therefore, it is necessary to develop a very effective catalyst for improving OER performances. The electronic properties and morphological structure of electrocatalysts can significantly affect their OER performance. Electrocatalysts with the morphology of dendrite can expose more active sites which would enhance the OER activity. Here, the 3D dendritic Ni@Ni(Fe)OOH core-shell material has been developed on nickel foam (NF) with a controllable morphology and composition using an extremely simple and fast method. The doping of Fe can effectively modulate the morphology and the electronic structure of Ni@NiO to improve the intrinsic activity of active sites. The porous dendritic core-shell structure could allow more active sites to grow and transport electrolyte faster. At the same time, the internal Ni core can work as fast electronic transfer networks. As a result, the optimized Ni@Ni(Fe)OOH/NF shows a great catalytic performance for OER with an overpotential of 226 mV cm−2 at 10 mA cm−2 and an excellent stability in alkaline solution. The results given in paper may bring important implications for the development of a series of hydrogen and oxygen catalysts.

Spray mixing and combustion processes are regarded as the major factors that determine the energy conversion efficiency and emission level of internal combustion engines. However, the related researches mainly rely on 3D flow simulation or optical engine experiments, which are highly expensive and time-consuming. In order to provide a more convenient solution, this paper developed a one-dimensional semi-phenomenological model to achieve accurate and efficient predictions on spray combustion characteristics. The model was constructed by a dimensionless spray theoretical model and limited experimental data of macroscopic spray characteristics. Inside the proposed model, a physical module was used to physical module spray air-fuel mixing conditions like fuel distribution and evaporation. Besides, an improved Arrhenius-typed correlation concerning injection parameters and environment variables was introduced to describe the chemical ignition characteristic of spray combustion. The optical experiment results showed that this method is simple and effective, and the forecasting is satisfactory. Based on the new model, the influences of blending n-pentanol on the spray combustion characteristics of diesel and biodiesel were investigated. On the physical aspect, the critical fuel concentration at liquid length position decreases with n-pentanol is blended into both fuels in the most cases, but witnessed a significant leap in 1200 K condition, especially for diesel blends; the physical ignition delay times of both diesel and biodiesel blends decreases first and go up later. On the chemical aspect, the join of n-pentanol caused the gap between the physical delay time and the chemical delay time much narrower, but the ignition patterns were different in diesel blends and biodiesel blends. Moreover, this paper proposed a series of correlations focused on the liquid length and ignition delay of n-pentanol blends sprays. These correlations covered wide conditions and showed better prediction accuracy than traditional ones.

To investigate effects of various compression ratios (CRs) and spark timing on characteristics of performance and emissions, a high CR six-cylinder heavy-duty compression ignition diesel engine was modified into the port fuel injection hydrogen and liquefied methane gas lean-burn heavy-duty SI engine and tested by using 13.6 and 14.0 CRs. Combination of alternative fuels, high CRs and control strategies was implemented in this study. Results indicated that the equivalent fuel consumption (EFC) dramatically decreased with increase of the hydrogen energy share. Additionally, the EFC reduced as higher CR was adopted. The brake thermal efficiency (BTE) firstly increased and then declined with increase of the hydrogen energy share. Besides, the BTE increased with CR. The maximum additional 1.8% of BTE was obtained by employing higher CR (14.0) for a specific operating condition. Furthermore, the NOX emissions remarkably ascended while the HC emissions significantly declined with increase of the hydrogen energy share. The CO emission formation did not show a strong relationship with the hydrogen energy share and the CR. However, the CO2 emission gradually declined with increase of the percentage of hydrogen and CR.

In this study, the chassis dynamometer tests for a gasoline-powered passenger vehicle were carried out under cold start and warm-up NEDC. The operating states, combustion and performance parameters of engine were measured continuously during vehicle driving cycles. Then, the combustion and thermodynamics processes under cold start and warm-up NEDC were compared and the influence factors for their differences were revealed. Results show that, since valve timing of tested engine is almost the same under cold start and warm-up conditions, it is not the main influence factor for the differences of in-cylinder RGF and EER. Although in-cylinder RGF decreases during cold start NEDC, the gap is too small to make any difference. Only in the early stage of NEDC, cold start has an obvious influence on in-cylinder combustion and thermodynamics processes of engine. For example, sparking timing is retarded, and SOC as well as 50% combustion position is further retarded. However, the heat transfer loss is also reduced due to the lower combustion temperature, thus the influence of later sparking timing on the indicated thermal efficiency of engine is restricted to some extent under cold start condition. All these provide theoretical guidance for improving engine actual performance.

The design and synthesis of highly efficient electrocatalysts for OER are important for energy storing applications. In this communication, Cu(TCNQ)2 nanorod arrays have been designed and synthesized successfully with a Cu(Fe)OOH nanosheet shell by using a short oxidation process of Cu(TCNQ)2 and subsequently an ultrafast ion exchange reaction. They are expected to combine a variety of desired merits including a simple and rapid preparation process, a large specific surface area, high conductivity and multiple electrocatalytic active sites. All the worthy characteristics which make Cu(TCNQ)2@Cu(Fe)OOH are endowed with an excellent OER catalytic performances with the required overpotential of 261 mV at 25 mA cm−2 only. The present work not only produces a good OER catalyst but also provides us a new idea to design efficient OER electrocatalysts.

In this research, the computational fluid dynamics (CFD) coupled with reduced chemical kinetic model was applied to study the combustion process and emissions characteristics of a NG-diesel dual fuel engine at various injector spray angles. The model was validated by measured data of in-cylinder pressure, heat release rate (HRR) and emissions (nitrogen oxide (NOx), hydrocarbons (HC), carbon monoxide (CO)) in the NG-diesel dual fuel engine. The validated CFD models were used to investigate the immediate process of combustion and emissions of NG-diesel dual fuel engine with the variation of spray angle. The results showed that the peak cylinder pressure increases as the spray angle increases from 60° to 140°, but slightly decreases if the spray angle continues to increase to 160°. Except for the condition of 1000 rpm and 50% load, the start of combustion (SOC), CA50, 10–50% combustion duration, CA90, 50–90% combustion duration and 10–90% combustion duration decrease as the spray angle increases from 60° to 120°, and keep minor fluctuations when the spray angle increases from 120° to 160°. The NOx emissions ascend when the spray angle increases from 60° to 140° and changes little if it continues to increase from 140° to 160°. Nevertheless, the unburned methane is almost unchangeable at 1000 rpm and 100% load. When the spray angle ranges between 120° and 160°, the CO emissions keep at a lower level. All these have provided visual data and theoretical guidance for improving the combustion and emissions performance of NG-diesel dual fuel engine.

The compatible catalytic structure of NiCo2O4 was modified into multi-shelled hollow spheres by one-pot synthesis, followed by heat treatment. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer–Emmet–Teller (BET) and N2 adsorption–desorption approaches were used for the characterizations of nanoparticles and multi-shelled hollow porous structures and the morphologies and crystal structures of these hollow spheres, respectively. Differential scanning calorimetry (DSC) was adopted for comparing the thermal decomposition performances of ammonium perchlorate (AP) catalyzed by adding different contents of multi-shelled NiCo2O4 hollow spheres. Impressively, the experimental results showed that the NiCo2O4 hollow spheres exhibited more excellent catalytic activity than NiCo2O4 nanoparticles as a result of their large specific surface areas, good adsorption capacity and many active reduction sites. The decomposition temperature of AP with multi-shelled NiCo2O4 hollow spheres could be reduced up to 322.3 °C from 416.3 °C. Furthermore, a catalytic mechanism was proposed for the thermal decomposition of AP over multi-shelled NiCo2O4 hollow spheres based on electron transfer processes.

Motorcycles are one of the main transportations in many Asian countries, and the huge amount of motorcycles in developing countries face various challenges, such as safety, increasing fuel price and air pollution. Previous studies observed that, the ratios of mean emission in g/km from motorcycles and cars are very high, especially for HC in urban driving. The motorcycle industry is now faced with the pressure of emission regulation upgrade. In the present study, the possibility and degree of emission (especially for HC) reduction through lean burn were tried to be explored. In this paper, the HC emissions were studied by experimental measurements and combined simulations on a twin-spark motorcycle gasoline engine over a wide range condition. The appearance HC amount, detailed reaction pathway and intermediate products were thoroughly investigated, and the main interest is the influences of relative air/fuel ratio. The results illuminated that, the overall trend of engine-out HC amount decreases as relative air/fuel ratio becomes larger. For example, when λ changes from 0.85 to 1.2, at 100% engine load the HC amount drops, by ∼55% and ∼53% for 3000 rpm and 4000 rpm, respectively. Besides, the PAHs (polycyclic aromatic hydrocarbons), soot and SOA (secondary organic aerosol) formation potentials were also analyzed in this paper. The results and analysis process indicated that, the combined simulation (between the GT-Power and ChemKin) is a useful tool to analyze the formation process of pollutants during combustion.

In this study, the main objective of the work was to evaluate the injection strategies on the cycle-to-cycle variations of a turbocharged DISI engine fueled with ethanol and gasoline blend by using single injection (SI) and two-stagnation injection strategy (TSIS) modes, respectively. Two-stagnation injection strategy modes were adopted to control the first injection and the later second injection by changing the injection timing or the second fuel mass repartition. The cycle-to-cycle variations of the in-cylinder pressure, peak pressure and its location, maximum rate of pressure rise and its location, indicated mean effective pressure and combustion phasing were statistically analyzed and comprehensively compared with various injection strategies. Results showed that employing TSIS 3 mitigated the in-cylinder pressure fluctuation and concentrated the integral heat release compared with other injection strategies. Meanwhile, adopting TSIS 3 obtained the lowest COVPP (5.63%) and achieved the frequency distributions of peak pressure histograms in a relatively narrow range. Furthermore, the cycle-to-cycle variations of the 10–90% combustion duration were relatively small and less sensitive to change the injection strategy modes. Finally, employing TSIS 3 was proved to be the optimal injection strategy for achieving the lowest COVIMEP while obtaining the highest IMEP.

Mitochondrial dysfunction is a key feature of injury to numerous tissues and stem cell aging. Although the tissue regenerative role of mesenchymal stem cell (MSC)-derived extracellular vesicles (MSC-EVs) is well known, their specific role in regulating mitochondrial function in target cells remains elusive. Here, we report that MSC-EVs attenuated mtDNA damage and inflammation after acute kidney injury (AKI) and that this effect was at least partially dependent on the mitochondrial transcription factor A (TFAM) pathway. In detail, TFAM and mtDNA were depleted by oxidative stress in MSCs from aged or diabetic donors. Higher levels of TFAM mRNA and mtDNA were detected in normal control (NC) MSC-EVs than in TFAM-knockdown (TFAM-KD) and aged EVs. EV-mediated TFAM mRNA transfer in recipient cells was unaffected by transcriptional inhibition. Accordingly, the application of MSC-EVs restored TFAM protein and TFAM-mtDNA complex (nucleoid) stability, thereby reversing mtDNA deletion and mitochondrial oxidative phosphorylation (OXPHOS) defects in injured renal tubular cells. Loss of TFAM also led to downregulation of multiple anti-inflammatory miRNAs and proteins in MSC-EVs. In vivo, intravenously injected EVs primarily accumulated in the liver, kidney, spleen, and lung. MSC-EVs attenuated renal lesion formation, mitochondrial damage, and inflammation in mice with AKI, whereas EVs from TFAM-KD or aged MSCs resulted in poor therapeutic outcomes. Moreover, TFAM overexpression (TFAM-OE) improved the rescue effect of MSC-EVs on mitochondrial damage and inflammation to some extent. This study suggests that MSC-EVs are promising nanotherapeutics for diseases characterized by mitochondrial damage, and TFAM signaling is essential for maintaining their regenerative capacity.

Gas-wetting alteration is a versatile and effective approach for alleviating liquid-blockage that occurs when the wellbore pressure of a gas-condensate reservoir drops below the dew point. Fluorochemicals are of growing interest in gas-wetting alteration because of their high density of fluorine groups and thermal stability, which can change the reservoir wettability into more favorable conditions for liquids. This review aims to integrate the overlapping research between the current knowledge in organic chemistry and enhanced oil and gas recovery. The difference between wettability alteration and gas-wetting alteration is illustrated, and the methods used to evaluate gas-wetting are summarized. Recent advances in the applications of fluorochemicals for gas-wetting alteration are highlighted. The mechanisms of self-assembling adsorption layers formed by fluorochemicals with different surface morphologies are also reviewed. The factors that affect the gas-wetting performance of fluorochemicals are summarized. Meanwhile, the impacts of gas-wetting alteration on the migration of fluids in the pore throat are elaborated. Furthermore, the Wenzel and Cassie-Baxter theories are often used to describe the wettability model, but they are limited in reflecting the wetting regime of the gas-wetting surface; therefore, a wettability model for gas-wetting is discussed. Considering the promising prospects of gas-wetting alteration, this study is expected to provide insights into the relevance of gas-wetting, surface morphology and fluorochemicals, further exploring the mechanism of flow efficiency improvement of fluids in unconventional oil and gas reservoirs.

Chronic wounds are still a type of intractable medical problem for both clinicians and researchers and cause a huge social and medical burden. Current clinical approaches can only manage the wounds but have limited capacity to promote the regeneration of chronic wounds. As a type of natural nanovesicles, extracellular vesicles (EVs) from multiple cell types ( e.g. , stem cells, immune cells, and skin cells) have been shown to participate in all stages of skin wound healing including inflammation, proliferation, and remodeling, and displayed beneficial roles in promoting wounds repair. Moreover, EVs can be further re-engineered with genetic/chemical, or scaffold material-based strategies for enhanced skin regeneration. In this review, we provided an overview of EV biology and discussed the current studies regarding the roles of EVs in chronic wound healing, particular in immune regulation, cell proliferation and migration, angiogenesis, and extracellular matrix remodeling, as well as the therapeutic effects of EVs on chronic wound by genetic modifications, combination with functionalized biomaterials, and as drug carriers. We also discussed the challenges and perspectives of translating EV-based therapies into clinical wound care in future.

In this study, the inhibition property of an organosilicate polymer was investigated as an inhibitor for water-based drilling fluids. A novel polymer was prepared using 2-acrylamido-2-methylpropane sulphonic acid (AMPS), N, N-dimethyl acrylamide (DMAA), maleic anhydride (MA), and γ-methacryloxypropyl trimethoxy silane (MEMO) as the polymerisation monomers, named as ADMM. Also, the inhibition performance was evaluated by an immersion test, a linear swelling test, and a shale cuttings recovery test. Compared with that of the other inhibitors, the addition of ADMM can effectively inhibit the swelling of mud balls, resulting in the lowest swelling height of the drilling fluid. ADMM was characterised using a thermogravimetric analysis, a Fourier transform infrared spectrometer, a nuclear magnetic resonance instrument, a laser particle size distribution instrument, and a zeta potentiometric analyser. The results showed that the decomposition temperature of ADMM was 330 °C. The shale cuttings recovery of the 1.0% ADMM solution at 150 °C was 76.32%. The dynamic shear rise rate was as low as 160%. Furthermore, ADMM was adsorbed on the clay surface at many points to form a “protective film” of the polymer, thus inhibiting the hydration of the clay.

A comparative investigation was conducted on a turbocharged direct-injection spark-ignition engine fuelled with gasoline and ethanol blend. Influences of single injection (SI) and two-stagnation injection strategy (TSIS) on thermodynamic process and performance of the engine operated on part-load condition were discussed and compared in this paper. The results indicated that 50% combustion position was slightly shifted to TDC and 10–90% combustion duration was shortened by using TSIS modes as compared with SI mode. However, the coefficient of variation in the indicated mean effective pressure was significantly increased with the second injection fuel mass repartition. In addition, the brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) were increase by adopting the TSIS modes, but the increase amplitude of BTE and BSFC was decreased, and even deteriorated in TSIS 6 mode. In comparison with SI mode, Hydrocarbon and carbon monoxide were declined with advanced second injection timing while both of them increased with increasing second injection fuel mass repartition. Moreover, NOx emissions were dramatically reduced by utilizing TSIS modes. Eventually, CO2 emission was mainly related to the carbon atom content, combustion efficiency and heat-work conversion in-cylinder.

An experimental investigation was conducted on the performance, combustion and knock characteristics of a high compression ratio, lean-burn heavy-duty spark ignition (SI) engine fuelled with n-butane and liquefied methane gas blend. Specifically, some technical adaptations were carried out on the original compression ignition (CI) engine for changing the direct fuel injection system into the electronic controlled intake port gas injection and implementing a high-energy ignition system. Results indicate that the in-cylinder pressure, heat release rate and cumulative heat release amount increase with the increased n-butane energy share. Once the n-butane energy ratio exceeds 5% in 1400 r/min, full-load, light knock occurs at this operating condition. In addition, the 50% burning location is advanced, the 10–90% combustion duration is shortened, and knocking intensity is strengthened. Furthermore, the maximum pressure rise rate fluctuates around the average value, and the oscillation amplitude also ascends with increased n-butane energy share which results in higher cycle-by-cycle variation. However, the IMEP and indicated thermal efficiency firstly go up with the increased percentage of the n-butane energy share and then decrease.

Recently, diesel/biodiesel/alcohol blend fuels have attracted tremendous attention as a potential alternative fuel in internal combustion engines, because of their beneficial effects on pollution emission and engine performance. However, there are few chemical mechanisms to forecast combustion characteristics of the ternary blends, especially for those blending with long-chain alcohols, such as butanol and pentanol. The objective of this paper is to develop a combined reduced combustion mechanism for the combustion simulation of diesel/biodiesel/alcohol (up to n-pentanol). This new combined mechanism, consisting of 229 species and 902 elementary reactions, was constructed by integrating two separated reduced mechanisms; one is the PRF-alcohols’ mechanism (Liu et al., 2016), and another is the biodiesel mechanism (Luo et al., 2012). The new combined mechanism reproduced well predictions of fuel ignition and flame speed compared with those obtained using the original ones. Extensive validations were performed against various experimental data for 0-D homogenous systems, 1-D freely propagating premixed flames and 3-D spray combustion flames. The proposed combined mechanism was shown to be versatile and robust, successfully integrating the biodiesel reaction mechanism and the long-chain alcohol reaction mechanisms into a single reaction scheme. Coupling with advanced simulation technology, it could be a powerful numerical tool in the design and optimization of new generation engines which are fueled with clean alternative fuels, especially when concerning long-chain alcohols. In addition, the effects of adding biodiesel and different kinds of alcohols on fundamental combustion characteristics of diesel/biodiesel/alcohol blend fuels were investigated using the proposed combined mechanism.

For a vehicle engine, it usually operates under transient conditions, and the transient behaviors represent its actual performance. In order to improve the actual performance of GDI engine during vehicle driving cycles, the vehicle test was conducted under new European driving cycle (NEDC), and the thermodynamics, combustion and emission characteristics were tested. Then, the transient performance of GDI engine was compared with the steady-state behaviors. In this way, the differences in various performance parameters under NEDC and steady-state conditions were demonstrated, and the reasons were revealed. Results show that, the spark timing, start of combustion (SOC), ignition delay, 50% combustion location and 10–90% combustion duration of GDI engine under NEDC deviate from their steady-state values seriously especially at low load, resulting in the large combustion instability. The consistency of pumping mean effective pressure (PMEP) under NEDC and steady-state conditions is satisfactory, while the indicated thermal efficiency has a large fluctuation during NEDC, and in most cases it is lower than the steady-state values. Both the transient HC and CO emissions are larger than the steady-state values especially at low load, while the transient NOx emission during NEDC is less than the steady-state values. All those not only demonstrated the change rules of combustion and emission characteristics of GDI engine under NEDC, but also provided guidance for improving the actual performance of vehicle engine.

Traditional oil-based drilling muds (OBMs) have a relatively high solid content, which is detrimental to penetration rate increase and reservoir protection. Aimed at solving this problem, an organoclay-free OBM system was studied, the synthesis methods and functioning mechanism of key additives were introduced, and performance evaluation of the system was performed. The rheology modifier was prepared by reacting a dimer fatty acid with diethanolamine, the primary emulsifier was made by oxidation and addition reaction of fatty acids, the secondary emulsifier was made by amidation of a fatty acid, and finally the fluid loss additive of water-soluble acrylic resin was synthesized by introducing acrylic acid into styrene/butyl acrylate polymerization. The rheology modifier could enhance the attraction between droplets, particles in the emulsion via intermolecular hydrogen bonding and improve the shear stress by forming a three-dimensional network structure in the emulsion. Lab experimental results show that the organoclay-free OBM could tolerate temperatures up to 220 °C and HTHP filtration is less than 5 mL. Compared with the traditional OBMs, the organoclay-free OBM has low plastic viscosity, high shear stress, high ratio of dynamic shear force to plastic viscosity and high permeability recovery, which are beneficial to penetration rate increase, hole cleaning and reservoir protection. Key words: organoclay-free, oil-based drilling mud, rheology modifier, emulsifier, fluid loss reducer, weak gel, reservoir protection

In our previous work, linear polyelectrolyte cross-linker-bridged hydrogel showed fast gelation within hours, which constrained in-depth deployment of such gels. In the present report, precipitation polymerization of bifunctional VBCTHt monomers in ethanol and acetonitrile generated the nano-gel cross-linkers bearing cyclic sulfonium moieties. The addition of nano-gels cross-linkers to partially hydrolyzed poly(acrylamide) formed covalently cross-linked in situ gels at the temperatures greater than 25 °C. As the morphology of the cross-linker changed from linear form to nano-gel in the state of sphere, the gelation time was controlled from 3 to 40 h. Nano-gel–HPAM system showed three orders of magnitude of delayed gelation while maintaining comparable mechanical integrity in comparison with conventional metallic cross-linked in situ gel, where sulfonium-functionalized nano-gel cross-linkers acting as covalent gelator were utilized for in situ gel formation. The change in cross-linker morphology and bonding nature of the gels dramatically extended gelation time. The mechanics of nano-gel cross-linker-derived covalently cross-linked HPAM in situ gels could be tuned by nano-gel cross-linkers concentration. The viscosity of HPAM and ionic cross-linker gelant had lower viscosity compared to conventional Cr3+–HPAM gel system as confirmed by rheological measurements. The gelant showed excellent salt and pH resistance, rendering it applicable to reservoir conditions. We believe this pioneer work in examination of cross-linker morphology to dictate hydrogel gelation offered the possibility to deploy mechanically tunable gels with delayed gelation for in-depth treatment of reservoir formation to improve fossil energy recovery.

Integrating the advantages of inorganic and polymeric nanoscale plugging agents, this paper introduced the synthesis of a nanoscale acrylic resin/nano-SiO2 composite (AR/SiO2) with a core-shell structure for water based drilling fluid (WBM), which can enhance the plugging efficiency of shale pores, reduce fluid invasion and improve wellbore stability in shale gas drilling process. The core-shell structure of AR/SiO2 was characterized by transmission electron microscope (TEM). Thermal Gravity Analysis (TGA) indicated the thermal resistance of AR/SiO2 up to 250 °C. Theoretical analysis implied that improved plugging property of AR/SiO2 might be due to good adhesion of deformable shell parts with shale matrix and the supporting provided by rigid core parts. The plugging ability was evaluated by pressure transmission tests and N2 adsorption tests. The results demonstrated that WBM containing AR/SiO2 can substantially enhance plugging efficiency and reduce fluid invasion. Characterization of filter cakes revealed that AR/SiO2 improved the quality of filter cakes, which resulted in a considerable improvement in filtration properties.

VVL and VVT are two common approaches to reduce engine pumping loss at part loads, however, the comparative study on their potentials and influence factors of pumping loss reduction is scarce. In this paper, the gas exchange processes of CVVL and VVT engines were investigated by bench testing. The mechanism and influence factors of pumping loss in the two types of engines were comparatively analyzed, the theoretic limitations of pumping loss in intake process were deduced and the suggestions to approach the theoretic minimum were proposed. The results show that the gross indicated mean effective pressure (IMEP) of engine is approximately proportional to cylinder pressure at bottom dead center (BDC) for both traditional throttle control strategy and early intake valve closing (EIVC) strategy. The difference of pumping losses between CVVL and VVT engines results from intake process. Due to the differences of intake modes, the CVVL engine has lower intake loss than VVT engine by nature. The pumping loss in intake process of CVVL engine is much closer to the theoretical minimum, and the BSFC of CVVL engine can be reduced by more than 20% at 2000 r/min and 2.3 bar IMEP by increasing the maximum lift of intake valve. All these have provided guidance for pumping loss reduction of gasoline engine.

Due to complex seepage mechanism and weak reservoir property, CBM requires being exploited by hydraulic fracturing. In order to comprehend the influencing laws of fracturing parameters' on productivity, recovery efficiency, and well network thoroughly, this paper establishes a non-linear gas-water percolation model of fractured wells. Stress deformations, fluid–structure interaction, CBM desorption, and diffusion research are done. On top of the above, injection pressure-drop well test method is adopted to evaluate fracturing effects. The result demonstrates that the reservoir porosity initially declines and subsequently rises. Permeability is non-linearly affected by threshold pressure gradient. Well space optimization involves fracture orientation, fracture penetration ratio, and fracture conductivity impacts. The rectangle and rhombus well pattern selection refers to reservoir anisotropy critical ratio. The injection pressure-drop test interpretation should be improved further due to the changes in wellbore liquid level. This study is of great significance to improve fracturing evaluation and parameters optimization. Keywords: CBM reservoir, Fluid-mechanical coupling analysis, Fracturing parameters optimization, Well test interpretation

Supramolecular chemistry provides a facile and feasible method to construct desired compounds via noncovalent interactions. Based on the host-guest recognition, the surfactant/cyclodextrin (CD) inclusion exhibited the excellent performance in potential application of various fields. The sodium dodecyl sulfate (SDS)/β-CD inclusion was introduced to chemical enhanced oil recovery. The fabrication of SDS/β-CD inclusion seriously affected the SDS ability to reduce the interfacial tension (IFT) between a model oil (toluene and n-decane, v/v = 1:1) and water, which may be the key factor to reduce the adsorption loss of SDS molecules via the addition of β-CD molecules. To reactivate the interfacial activity of SDS molecules, we employed the adamantanamine chloride (AD) to the SDS/β-CD inclusion solutions. Interestingly, the electrostatic attraction between AD/β-CD inclusion and SDS molecule dominated the change tendency of IFT values, which was further verified by the systematical investigations on the salinity and temperature effects on the IFT.

In this study, the thermodynamics, combustion and emission characteristics of a NG-diesel dual fuel engine with varying pilot injection degree at low speed and low load were investigated by computational fluid dynamics (CFD) simulation and bench test. Based on tested in-cylinder pressure, the in-cylinder combustion process of NG-diesel dual fuel engine was quantitatively analyzed. On this basis, both the one-dimensional and three-dimensional CFD simulated models were built and then validated by tested data, which were used to analyze the combustion and emission characteristics of NG-diesel dual fuel engine. From this study, the effects of advanced pilot injection degree (APID) on the thermodynamics, combustion and emission characteristics of NG-diesel dual fuel engine were found. With the advancing of pilot injection degree, both the SOC and 50% combustion position are advanced, which leads the maximum in-cylinder pressure and heat release rate (HRR) to increase. The 10–50% combustion duration decreases slightly but the 50–90% combustion duration increases obviously. Meanwhile, both the effective expansion efficiency (EEE) and the percent of heat transfer loss increase, while their increase rates are different, which make the brake thermal efficiency (BTE) firstly increase and then decrease. The BSNOx increases largely while the BSTHC is almost unchanged with the advance of injection timing. Although more HC is generated in the early stage as the pilot injection degree is retarded, the post-combustion becomes clear which accelerates the oxidation of HC. All these have provided theoretical guidance and data support for improving the performance of NG-diesel dual fuel engine.

In this study, the combustion and emission characteristics of a turbocharged GDI engine under cold start NEDC were investigated based on chassis dynamometer test. The operating states, combustion and emission performance of GDI engine were measured continuously during vehicle driving cycles. Then, the combustion and emission characteristics of GDI engine under cold start NEDC were obtained and the influence factors were revealed by synchronous analysis of various operating parameters. The results show that, the combustion duration from start of combustion (SOC) to 50% combustion location changes a little under cold start NEDC. At most time, the 10–90% combustion duration usually changes in the range of 20–40 °CA, which turns longer under idling conditions but shorter under acceleration conditions. Since the sparking timing is severely retarded in the beginning stages of NEDC, the effect of cold start on hydrocarbon (HC) emission is very limited. HC emission increases sharply under deceleration conditions, due to the decrease of engine indicated mean effective pressure (IMEP). Carbon monoxide (CO) emission does not seem to have relevance to the cold start condition, and it is very sensitive to excess air coefficient while the effects of other parameters are very little. Nitrogen oxide (NOx) emission increases under acceleration conditions but decreases under deceleration conditions, which is mainly influenced by the IMEP, then followed by engine speed. All those not only demonstrated the change rules of combustion and emission characteristics of turbocharged GDI engine under cold start NEDC, but also provided the guidance for improving the vehicle emission performance.

Persistent mitochondrial injury occurs after acute kidney injury (AKI) and mitochondria-targeted antioxidant Mito-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) (MT) has shown benefits for AKI, but its efficiency is limited by short half-life and side effect in vivo. Self-assembling peptide (SAP) hydrogel is a robust platform for drug delivery. This study aims to develop an SAP-based carrier to slow release MT for enhancing its long-term therapeutic potency on AKI. The KLD with aspartic acid (KLDD) was designed. The microstructure and in vitro release of MT was assayed. The protective role of MT-loaded SAP (SAP-MT) hydrogel on renal mitochondrial injury, tubular apoptosis, and inflammation was evaluated in mice at five days after ischemia-reperfusion injury (IRI). Our results showed that KLDD could self-assemble into cross-linked nanofiber hydrogel and it had lower release rate than free MT and KLD hydrogel. Compared to IRI and free MT mice, SAP-MT mice exerted reduced renal mitochondria-produced ROS (mtROS) and improved mitochondrial biogenesis and architecture. Consequently, SAP-MT mice showed less renal tubular cell apoptosis, kidney injury marker kidney injury molecule-1 (Kim-1) expression, lower level of pro-inflammatory factors expression, and macrophages infiltration than those of IRI and free MT mice. This study suggested that SAP-MT ameliorated IRI due to its extended mitochondrial protection role than free MT and thus improved the long-term outcomes of AKI.

This study presents an alternative method to enhance the emulsion stability of oil based drilling fluids (OBMs). Modified dimer acid (MDA) was synthesized with a molecular structure having two hydrophilic heads and two hydrophobic tails. Theoretically, the adsorption of MDA on an oil–water interface makes it possible to increase hydrogen bonding between water droplets and form three dimensional networks which benefit emulsion stability. The influence of MDA on the stability of base emulsions was studied by visual observation. Then the stabilization mechanism of MDA was analyzed from the micro and macro points of view by morphology study using a cryo-scanning electron microscope (cryo-SEM) and rheological measurements including viscosity vs. shear rates, zero-shear viscosity (η0), and creep and recovery tests. Experimental results showed that a substantial improvement in emulsion stability was visually observed when the MDA concentration was 2 g L−1. From cryo-SEM observation, a honeycomb structure was observed in the emulsion containing 2 g L−1 MDA, which can provide a physical barrier to restrain the movement of water droplets. In comparison with the rheological behaviors of the emulsion without MDA, a remarkably larger zero-shear viscosity, a solid-like behavior and a greater elasticity were observed when 2 g L−1 MDA was present. Finally, the application in OBMs shows that MDA can largely enhance electrical stability (ES) and reduce the filtration volume. The method proposed in the paper could be used to enhance the stability of w/o emulsions in a variety of fields.

The acetone–butanol–ethanol (ABE) is the intermediate product during the bio-butanol fermentation process, and is widely considered as one of the promising alternative fuels in the diesel engine for its advantages of oxygenated fuels, better air–fuel mixing, lower NOx and soot emissions, and lower production cost. In this paper, different ABE ratios in the diesel fuel and injection timings were tested in the AVL diesel engine, and obtained the combustion and emission characteristics parameters for the late model calibration. Then, the CFD KIVA-3V code coupled with the CANTERA code was built and validated against the experimental data. Subsequently, different injection timings and exhaust gas recirculation (EGR) ratios were investigated on the diesel engine fuelled with the ABE/diesel blended fuel to unveil their effects on the combustion and emissions behaviors. The results indicated that the injection timing and EGR strongly affected the combustion process of the diesel engine fuelled with the ABE/diesel fuel. In addition, the oxidation and formation process of the intermediate species, soot precursors, final soot, NOx, CO and HC emissions in the diesel engine fuelled with the ABE/diesel fuel were also significantly impacted by the injection timing and EGR strategies.

The multifunctional assembly of amphiphilic ionic liquids (AILs) can play an important role in the synthesis of various composite nanomaterials. In this work, we developed a novel strategy to steer the generation of polymer/AIL16/Ag spheres by using amphiphilic ionic liquid, 1-hexadecyl-3-methylimidazolium chloride (AIL16) as a “bridge”. Two kinds of polymer spheres (poly(methyl methacrylate), PMMA or polystyrene, PS) were used to assemble of the PMMA/AIL16/Ag (or PS/AIL16/Ag) microspheres. Subsequently, the PMMA/AIL16/Ag (or PS/AIL16/Ag) microspheres and AIL16 were used as templating agents of macropores and mesoporores respectively to prepare Ag-decorated bimodal porous silica. The effects of mass ratios of m(Ag)/m(PMMA, or PS) and amount of AIL16 on the formation of the PMMA (or PS)/AIL16/Ag microspheres and the Ag-decorated bimodal porous silica structure were investigated in detail. It was found that the dispersity and loading capacity of Ag nanoparticles onto the polymer spheres and the structures of the bimodal porous silica can be easily manipulated by changing the mass ratios of m(Ag)/m(PMMA, or PS) and the amount of adding AIL16. The obtained Ag-decorated bimodal porous silica exhibited three dimensional ordered spherical macroporous array with an ordered mesoporous silica walls, in which Ag-NPs with good dispersibility were immobilized onto the inner walls of the macroporous holes. Furthermore, the synthesized Ag-decorated bimodal porous silica displayed a better catalytic activity for the reduction reaction of 4-nitrophenol by using NaBH4 as reducer.

In order to further improve thermal efficiency and fuel economy, the engine community pays more attention to the advanced controlling strategy. In this paper, the impacts of the continuous variable valve lift (CVVL) system and Miller cycle strategy on the performance behavior of the natural gas spark ignition (SI) engine were comprehensively investigated. The results indicated that pumping loss was decreased, and volumetric efficiency slightly increased with using CVVL. In addition, the intake air mass flow at the intake ports became more smooth, and turbulence flow and its intensity were strengthened with using CVVL, which were beneficial to accelerate combustion rate and improve combustion efficiency. Under the partial load of the 1200 rpm 5 bar, the ratio of the pumping mean effective pressure (PMEP) in indicated mean effective pressure (IMEP) was reduced by 2.74%. Furthermore, an extra 5.43% improvement of indicated thermal efficiency was obtained. On the other hand, peak in-cylinder pressure and peak combustion temperature of the natural gas SI engine operated on Miller cycle were decreased with late intake valve close (LIVC), particularly the pressure and temperature at the end of the compression stroke, which resulted in reducing NOx emissions formation and mitigating knocking combustion. However, the intake mass flow at the intake ports became fluctuation and the volumetric efficiency was decreased with using LIVC. In addition, brake specific fuel consumption was increased and indicated thermal efficiency decreased with employing LIVC.

The unprecedented development of global industrialization has accelerated the discharge of wastewater, organic pollutants and heavy metals in which pose great threats to human health and ecosystem due to their high toxicity and poor decomposition. In this work, a facile magnetic-responsive CNT/chitosan composite for multiple contaminants removal was constructed through a two-step approach, which exhibits impressive adsorption capacity toward organic contaminants and heavy metals, the adsorbed composite can be conveniently collected by applying an external magnetic field. Surface morphology and microstructure of the fabricated CNT/chitosan composite were characterized using scanning electron microscopy, scanning electron cryomicroscopy, and transmission electron microscopy. Fourier transform infrared spectroscopy, zeta potential, Thermogravimetric analysis, and X-ray diffraction were employed to investigate the modification mechanism and the interaction within the functional groups; the magnetic responsiveness of the composite is verified by the vibrating sample magnetometer. The prepared composite displayed better adsorption to organic Rhodamine B than to methyl orange due to the strong π-π electron-donor-acceptor interaction between the benzene ring of RhB and CNT. The adsorption capacity for heavy metals followed the order Fe3+>Cu2+>Pb2+>Zn2+, the organic contaminants and heavy metals removal by CNT/chitosan composite fit the pseudo-second-order kinetic model well, the preferable adsorption could be ascribed to the synergy of the π–π stacking and hydrophobic interaction of CNT and chelation interaction of chitosan. Recyclability of CNT/chitosan composite displays its great potential in multiple contaminants elimination from aqueous solutions.