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To grow films of Cu2O, bis-(dimethylamino-2-propoxide)Cu(II), or Cu(dmap), is used as an atomic layer deposition precursor using only water vapor as a co-reactant. Between 110 and 175 °C, a growth rate of 0.12 ± 0.02 A per cycle was measured using an in situ quartz crystal microbalance (QCM). X-ray photoelectron spectroscopy (XPS) confirms the growth of metal–oxide films featuring Cu(I).

Polymeric capsules often buckle, collapse or even break when being processed in the dried state into other materials under high temperature and pressure due to moderate mechanical rigidity. In the case of non-spherical capsules, to keep their precious anisotropic morphology intact under harsh conditions is even more challenging since the whole surface of such kinds of capsules does not experience the same stress or strain due to the different surface curvatures. In the current work, we reported a strategy to prepare polydopamine (PDA) capsules with an ellipsoidal shape and enhanced mechanical rigidity using polystyrene ellipsoids as the sacrificial anisotropic templates. Bio-inspired oxidation induced self-polymerization of dopamine can form conformal PDA coatings on polystyrene ellipsoids of various aspect ratios and sizes. Several strategies have been exploited to increase the thickness of the PDA shell, among which, iterating PDA coating produces ellipsoidal PDA capsules with a thick and robust shell. These ellipsoidal PDA capsules can survive carbonization at temperatures as high as 800 °C and were directly turned into N-doped carbon capsules with a well-defined ellipsoidal shape, excluding the necessity of removing the sacrificial templates after carbonation. Furthermore, the rigid PDA ellipsoidal capsules are efficient adsorbents for organic dyes in contaminated water and have impressive adsorption efficiencies as high as 200 mg g−1.

Mononuclear and dinuclear copper species were synthesized at the nodes of an NU-1000 metal-organic framework (MOF) via cation exchange and subsequent oxidation at 200 °C in oxygen. Copper-exchanged MOFs are active for selectively converting methane to methanol at 150-200 °C. At 150 °C and 1 bar methane, approximately a third of the copper centers are involved in converting methane to methanol. Methanol productivity increased by 3-4-fold and selectivity increased from 70% to 90% by increasing the methane pressure from 1 to 40 bar. Density functional theory showed that reaction pathways on various copper sites are able to convert methane to methanol, the copper oxyl sites with much lower free energies of activation. Combining studies of the stoichiometric activity with characterization by in situ X-ray absorption spectroscopy and density functional theory, we conclude that dehydrated dinuclear copper oxyl sites formed after activation at 200 °C are responsible for the activity.

Catalytic hydrogenation is an important process used for the production of everything from foods to fuels. Current heterogeneous implementations of this process utilize metals as the active species. Until recently, catalytic heterogeneous hydrogenation over a metal-free solid was unknown; implementation of such a system would eliminate the health, environmental, and economic concerns associated with metal-based catalysts. Here, we report good hydrogenation rates and yields for a metal-free heterogeneous hydrogenation catalyst as well as its unique hydrogenation mechanism. Catalytic hydrogenation of olefins was achieved over defect-laden h-BN (dh-BN) in a reactor designed to maximize the defects in h-BN sheets. Good yields (>90%) and turnover frequencies (6 × 10–5–4 × 10–3) were obtained for the hydrogenation of propene, cyclohexene, 1,1-diphenylethene, (E)- and (Z)-1,2-diphenylethene, octadecene, and benzylideneacetophenone. Temperature-programmed desorption of ethene over processed h-BN indicates the formation of a highly defective structure. Solid-state NMR (SSNMR) measurements of dh-BN with high and low propene surface coverages show four different binding modes. The introduction of defects into h-BN creates regions of electronic deficiency and excess. Density functional theory calculations show that both the alkene and hydrogen-bond order are reduced over four specific defects: boron substitution for nitrogen (BN), vacancies (VB and VN), and Stone–Wales defects. SSNMR and binding-energy calculations show that VN are most likely the catalytically active sites. This work shows that catalytic sites can be introduced into a material previously thought to be catalytically inactive through the production of defects.

Zr-based metal–organic frameworks (MOFs) have been shown to be excellent catalyst supports in heterogeneous catalysis due to their exceptional stability. Additionally, their crystalline nature affords the opportunity for molecular level characterization of both the support and the catalytically active site, facilitating mechanistic investigations of the catalytic process. We describe herein the installation of Co(II) ions to the Zr6 nodes of the mesoporous MOF, NU-1000, via two distinct routes, namely, solvothermal deposition in a MOF (SIM) and atomic layer deposition in a MOF (AIM), denoted as Co-SIM+NU-1000 and Co-AIM+NU-1000, respectively. The location of the deposited Co species in the two materials is determined via difference envelope density (DED) analysis. Upon activation in a flow of O2 at 230 °C, both materials catalyze the oxidative dehydrogenation (ODH) of propane to propene under mild conditions. Catalytic activity as well as propene selectivity of these two catalysts, however, is different under the same experimental conditions due to differences in the Co species generated in these two materials upon activation as observed by in situ X-ray absorption spectroscopy. A potential reaction mechanism for the propane ODH process catalyzed by Co-SIM+NU-1000 is proposed, yielding a low activation energy barrier which is in accord with the observed catalytic activity at low temperature., Metal−organic framework supported cobalt oxides catalyze the oxidative dehydrogenation of propane with high propene selectivity at low temperature.

The catalytic performance of a cobalt(II) single-site catalyst supported on the zirconia-like nodes of the metal organic–framework (MOF) NU-1000 is herein characterized by quantum chemical methods and compared to an iso-structural analogue incorporating nickel(II) as the active transition metal. The mechanisms of atomic layer deposition in MOFs and of catalysis are examined using density functional theory. We compare the catalytic activity of Co and Ni installed on the zirconia-like nodes for ethylene dimerization, considering three plausible pathways. Multiconfigurational wave function theory methods are employed to further characterize the electronic structures of key transition states and intermediates. Finally, we report confirmation of Co catalytic activity for ethylene dimerization from experiments that were prompted by the computational prediction.

It is well recognized that building form has significant influences on energy performance in buildings, especially in the cold climate. It is imperative to understand the relationship between built forms and energy use in order to provide guidance in early project stage such as preliminary design. Therefore, this study focuses on two aspects to understand characteristics of energy use due to the change of parameters related to building form. The first aspect is to apply new metamodel global sensitivity analysis to determine key factors influencing energy use and the second aspect is to develop reliable fast-computing statistical models using state-of-art machine learning methods. An office building, located in Harbin, China, is chosen as a case study using EnergyPlus simulation program. The results indicate that non-linear relationships exist between input variables and energy use for both heating and electricity use. For heating energy, two factors (floor numbers and building scale) show a non-linear yet monotonic trend. For electricity use intensity, building scale is the only significant factor that has non-linear effects. It is also found that the ranking results of critical factors to both electricity use and heating energy per floor area vary significantly between small and large scale buildings. Neural network model performs better than other machine-learning methods, including ordinary linear model, MARS (multivariate adaptive regression splines), bagging MARS, support vector machine, random forest, and Gaussian process.

A heterobimetallic cobalt–aluminum complex was immobilized onto the metal organic framework NU-1000 using a simple solution-based deposition procedure. Characterization data are consistent with a maximum loading of a single Co–Al complex per Zr6 node of NU-1000. Furthermore, the data support that the Co–Al bimetallic complex is evenly distributed throughout the NU-1000 particle, binds covalently to the Zr6 nodes, and occupies the NU-1000 apertures with the shortest internode distances (∼8.5 A). Heating the anchored Co–Al complex on NU-1000 at 300 °C for 1 h in air completely removes the organic ligand of the complex without affecting the structural integrity of the MOF support. We propose that a Co–Al oxide cluster is formed in place of the anchored complex in NU-1000 during heating. Collectively, the results suggest that well-defined heterobimetallic complexes can be effective precursors for installing two different metals simultaneously onto a MOF support. The CoAl-functionalized NU-1000 samples catalyz...

Few-atom clusters composed of nickel and sulfur have been successfully installed into the Zr(IV)-based metal-organic framework (MOF) NU-1000 via ALD-like chemistry (ALD = atomic layer deposition). X-ray photoelectron spectroscopy and Raman spectroscopy are used to determine that primarily Ni(2+) and S(2-) sites are deposited within the MOF. In a pH 7 buffered aqueous solution, the porous catalyst is able to produce H2 gas at a rate of 3.1 mmol g(-1) h(-1) upon UV irradiation, whereas no H2 is generated by irradiating bare NU-1000. Upon visible light irradiation, little H2 generation was observed; however, with the addition of an organic dye, rose bengal, NiS-AIM can catalyze the production of H2 at an enhanced rate of 4.8 mmol g(-1) h(-1). These results indicate that ALD in MOFs (AIM) can engender reactivity within high surface area supports for applications in the solar fuels field.

Low-cost activated carbons were prepared from poplar wood by chemical activation with KOH as a chemical activating agent. The thermal behavior of KOH-impregnated poplar wood was analyzed in detail via the Thermogravimetric analysis (TG, DTG and DSC). Moreover, the effects of impregnation ratio, activation temperature and activation time on the porous structure were investigated. Results showed that KOH has catalytic effect which could promote the pyrolysis of poplar wood at lower activation temperature. The activated carbons from poplar wood with KOH activation could be formed at 550–700 °C. The specific surface area and pore volume of activated carbon increased with increasing the impregnation ratio, activation temperature and activation time. Moreover, influence of increasing impregnation ratio on the porosity of activated carbon is sensitive to activation time. The maximum specific surface area (1551 m2/g) activated carbon with uniform micropores distribution was obtained at activation temperature of 700 °C, impregnation ratio of 3/1 and activation time of 30 min. Carbon skeleton could break seriously when activation temperature is higher than 750 °C.

Two formamidinate bridged dirhodium(II,II) complexes with chelating diimine ligands L, [Rh2(μ-DTolF)2(L)2]2+, were shown to electrocatalytically reduce CO2 in the presence of H2O. Analysis of the reaction mixture and headspace following bulk electrolysis revealed H2 and HCOOH as the major products. The variation in relative product formation is discussed.

The effects of hydrogen addition on the emission and heat transfer characteristics of oxygen-enriched laminar methane diffusion flames were investigated in a laboratory-scale furnace with a co-axial burner. The volume fraction of hydrogen in the methane-hydrogen blend was varied from 0% to 50%, and the oxygen concentration was varied from 25% to 35%. Results showed that the addition of hydrogen led to an increase in the soot-free length and flame temperature while the degree of increase was less at higher oxygen concentrations. Adding hydrogen chemically enhanced the oxidation of CO to CO2, and this chemical effect was stronger when the oxygen concentration increased. NOx emissions increased significantly with the addition of hydrogen, while the rate of this increase decreased with greater oxygen concentrations. The total heat flux increased with the addition of hydrogen, while the rate of this increase was less at higher oxygen concentrations. Although the radiative heat flux increased with higher oxygen concentrations, it did not exceed 6% of the total heat flux at 35% O2. Moreover, adding hydrogen decreased the radiative heat flux; this decrease was significant at higher oxygen concentrations.

The enhanced permeability and retention (EPR) effect in human solid tumors is being increasingly questioned due to the failure of many nanomedicines in their clinical translation. Herein, we developed an ex vivo perfusion model for real-time investigation of the EPR effect in human renal tumors via X-ray computed tomography (CT), proving the EPR in human solid tumors and correlating the EPR effect in human tumors with that in animal models. Unexpectedly, more than 87 % of human renal tumors displayed a considerable EPR effect, which yet showed significant diversity and heterogeneity in different patients. For the first time, we unraveled that the EPR effect in renal tumors was positively correlated with the tumor size, and tumors from male patients exhibited a significantly higher EPR effect. This ex vivo model provides an efficient strategy for investigating the EPR effect in human tumors. Our results may provide a theoretical basis for the development of anticancer nanomedicines in the future.

Bayesian analysis has attracted more attention in calibrating building energy models since it can naturally account for uncertainty of input parameters. However, standard Bayesian analysis requires to compute likelihood functions to represent the probability of the observed data under a statistical energy model. This makes the implementation of standard Bayesian analysis difficult for calibrating dynamic building energy models. Therefore, this research proposes a new Bayesian method by combining the approximate Bayesian computation with machine learning techniques in calibrating building models without computing likelihood functions. The results indicate that this new Bayesian computation approach combined with the machine learning algorithms can provide fast and reliable calibration for building energy models created using the EnergyPlus program. The calibration metrics in terms of the coefficient variations of root mean square errors from this new Bayesian method are well below the threshold value (15%) recommended from the ASHRAE standard for monthly energy data. Moreover, the better calibration results can be obtained by using linear or nonlinear post-adjustment techniques to account for the differences between the simulated and observed energy data. The method proposed here can significantly extend the application of Bayesian analysis in calibrating building energy models under uncertainty due to its simplicity and fast computation. Furthermore, the new Bayesian approach combined with machine learning technique can also be used to calibrate the simulation-based models for various types of energy systems.

The metal-organic framework (MOF), NU-1000, and its metalated counterparts have found proof-of-concept application in heterogeneous catalysis and hydrogen storage among others. A vapor-phase technique, akin to atomic layer deposition (ALD), is used to selectively deposit divalent Cu ions on oxo, hydroxo-bridged hexa-zirconium(IV) nodes capped with terminal -OH and -OH2 ligands. The subsequent reaction with steam yields node-anchored, CuII-oxo, hydroxo clusters. We find that cluster installation via AIM (ALD in MOFs) is accompanied by an expansion of the MOF mesopore (channel) diameter. We investigated the behavior of the cluster-modified material, termed Cu-AIM-NU-1000, to heat treatment up to 325 °C at atmospheric pressure with a low flow of H2 into the reaction cell. The response under these conditions revealed two important results: (1) Above 200 °C, the initially installed few-metal-ion clusters reduce to neutral Cu atoms. The neutral atoms migrate from the nodes and aggregate into Cu nanoparticles. While the size of particles formed in the MOF interior is constrained by the width of mesopores (∼3 nm), the size of those formed on the exterior surface of the MOF can grow as large as ∼8 nm. (2) Reduction and release of Cu atoms from the MOFs nodes is accompanied by the dynamic structural transformation of NU-1000 as it reverts back to its original dimension following the release. These results show that while the MOF framework itself remains intact at 325 °C in an H2 atmosphere, the small, AIM-installed CuII-oxo, hydroxo clusters are stable with respect to reduction and conversion to metallic nanoparticles only up to ∼200 °C.

During the plasma modification process on activated carbon surface, reactive gas of O2 in the plasma field dominates the formation of oxygen-containing groups on activated carbon surface, which is a key factor that affects the mercury adsorption. Previous studies showed that change the O2 concentration would influence the generation of oxygen-containing groups and thus affect the mercury adsorption. It is important to investigate the effects of O2 concentration in the non-thermal plasma field on the mercury adsorption characteristic of modified activated carbon. This work presents the results of the novel use of non-thermal plasma in Ar-O2 gas to increase surface oxygen functionality on the surface of a commercially available biomass carbon. The volume fraction of O2 in the Ar-O2 mixture was varied from 10 % to 100 %. The surface physical and chemistry properties of modified activated carbon were analyzed by using BET, FT-IR and XPS techniques. Results showed that activated carbon modified by Ar-O2 non-thermal plasma showed significantly better mercury removal performance compared with the original activated carbon. Moreover, increase O2 concentration in the plasma field can further increase the mercury removal efficiency of modified activated carbon. Higher O2 concentration can produce more O radicals during plasma system and facilitated the formation of carbonyl and ester groups on activated carbon surface and thus enhanced the mercury removal. Temperature programmed desorption (TPD) results indicated that mercury reacted with ester groups were prior to carbonyl groups. When O2 concentration increased to 100 %, the ester groups of modified activated carbon dominated the mercury adsorption process.

© 2016 Elsevier Ltd. Energy assessment of urban buildings has become an active research field due to a large amount of energy consumed in cities as a result of fast urbanization. Hence, it is necessary to determine relative importance of variables for explaining variations of building energy use. However, two commonly used methods (correlation analysis and standardized coefficient) are only suitable for uncorrelated variables. This may not be the case for an extensive urban dataset containing social, economic, and physical variables. Therefore, this study proposes a two-stage approach to handle a large number of correlated variables in urban energy analysis. London has been chosen as a case study to determine influential factors affecting domestic energy use. The first stage applies two fast-computing methods (Genizi measure and correlation-adjusted score) to select important factors. The second stage implements two computationally intensive approaches (Lindeman Merenda Gold and proportional marginal variance decomposition) to further assess relative contributions of explanatory factors selected in the first step from conditional and marginal perspectives. The results indicate that this two-stage approach can deliver reliable results by explicitly accounting for correlations among variables in urban energy assessment.

[EN] In this paper, the effect of spray droplets on the coating of cold spherical particles was studied.The microcapsule granulator produces micron-sized droplets to coat the spherical particles in cold storage, and the high-definition camera and precision balance are used to photograph and weigh the particles before and after the spraying. The droplets are obtained by using the image and data processing technology coating area and coating quality, the droplet coating effect was evaluated by a number of dimensionless parameters such as coating ratio and mass ratio.By orthogonal design experiment and uncertainty analysis, the effects of droplet size and flow rate, spherical particle temperature and diameter on coating effect were studied, and the effect of droplet group coating on low temperature spherical particles was obtained., The authors acknowledge Projects supported by the National Natural Science Foundation of China (Grant No. 31571906 & No.21506163).

Zr-based metal-organic frameworks (MOFs) have been known for their excellent stability; however, due to the high connectivity of the Zr

Pullulan particles were prepared to improve water solubility. The pullulan droplet with the concentration of 5%, 10%, 15% or 20% (w/w) was injected and frozen in the cryogenic media of liquid nitrogen at −196 °C or cold air at −15 °C, then freeze dried. The results show that most of dried pullulan particles pre-processed in either liquid nitrogen or cold air can be completely dissolved in water within 60 s. The water solubility of as-prepared particles in liquid nitrogen is better than that in cold air. The particles frozen at −196 °C have smaller and more uniform pore structures together with a larger specific surface area than those frozen at −15 °C. It is found that the particles from 10% pullulan solution with liquid nitrogen have largest water solubility and also highest specific surface area (11.78 m2/g).

We report the syntheses, structures, and oxidation catalytic activities of a single-atom-based vanadium oxide incorporated in two highly crystalline MOFs, Hf-MOF-808 and Zr-NU-1000. These vanadium catalysts were introduced by a postsynthetic metalation, and the resulting materials (Hf-MOF-808-V and Zr-NU-1000-V) were thoroughly characterized through a combination of analytic and spectroscopic techniques including single-crystal X-ray crystallography. Their catalytic properties were investigated using the oxidation of 4-methoxybenzyl alcohol under an oxygen atmosphere as a model reaction. Crystallographic and variable-temperature spectroscopic studies revealed that the incorporated vanadium in Hf-MOF-808-V changes position with heat, which led to improved catalytic activity.

The kinetic effects of H2 addition on the thermal characteristics of laminar methane diffusion flames were numerically studied using a detailed chemical kinetics consisting of 53 species and 325 reactions. The variations in the heat release properties and relevant key reactions with H2 addition were analyzed. Results show that the reactions of H + O2 + H2O ⇔ HO2 + H2O (R35), H + HO2 ⇔ OH + OH (R46), H + CH3 (+ M) ⇔ CH4 (+ M) (R52) and OH + H2 ⇔ H + H2O (R84) present important roles in the global heat release and the contributions of these reactions significantly increased as H2 is added to CH4 stream. Moreover, the increase rate of contribution of R84 with H2 addition is much larger than those of the reactions of R35, R46 and R52. The H and OH are the two most important radicals for heat release in the combustion process of CH4-H2 diffusion flame. The reaction of R84 is one of the main contributors for production of H radical and the contribution of R84 significantly increased with H2 addition, while the reaction of H + O2 ⇔ O + OH (R38) dominates the contribution of production of OH, which contributes more than 50 %, no matter whether H2 is added to CH4 stream.

Formamidinate-bridged Rh2(II,II) complexes containing diimine ligands of the formula cis-[Rh2(II,II)(μ-DTolF)2(NN)2](2+) (Rh2-NN2), where DTolF = p-ditolylformamidinate and NN = dppn (benzo[i]dipyrido[3,2-a:2',3'-h]quinoxaline), dppz (dipyrido[3,2-a:2',3'-c]phenazine), and phen (1,10-phenanthroline), electrocatalytically reduce H(+) to H2 in DMF solutions containing CH3COOH at a glassy carbon electrode. Cathodic scans in the absence of acid display a Rh(III,II/II,II) reduction at -0.90 V vs Fc(+)/Fc followed by NN(0/-) reduction at -1.13, -1.36, and -1.65 V for Rh2-dppn2, Rh2-dppz2, and Rh2-phen2, respectively. Upon the addition of acid, Rh2-dppn2 and Rh2-dppz2 undergo reduction-protonation-reduction at each pyrazine-containing NN ligand prior to the Rh2(II,II/II,I) reduction. The Rh2(II,I) species is then protonated at one of the metal centers, resulting in the formation of the corresponding Rh2(II,III)-hydride. In the case of Rh2-phen2, the reduction of the phen ligand is followed by intramolecular electron transfer to the Rh2(II,II) core in the presence of protons to form a Rh2(II,III)-hydride species. Further reduction and protonation at the Rh2 core for all three complexes rapidly catalyzes H2 formation with varied calculated turnover frequencies (TOF) and overpotential values (η): 2.6 × 10(4) s(-1) and 0.56 V for Rh2-dppn, 2.8 × 10(4) s(-1) and 0.50 V for Rh2-dppz2, and 5.9 × 10(4) s(-1) and 0.64 V for Rh2-phen2. Bulk electrolysis confirmed H2 formation, and further CH3COOH addition regenerates H2 production, attesting to the robust nature of the architecture. The cis-[Rh2(II,II)(μ-DTolF)2(NN)2](2+) architecture benefits by combining electron-rich formamidinate bridges, a redox-active Rh2(II,II) core, and electron-accepting NN diimine ligands to allow for the electrocatalysis of H(+) substrate to H2 fuel.

Atomic layer deposition (ALD) has been employed as a new synthetic route to thin films of cobalt sulfide on silicon and fluorine-doped tin oxide platforms. The self-limiting nature of the stepwise synthesis is established through growth rate studies at different pulse times and temperatures. Additionally, characterization of the materials by X-ray diffraction and X-ray photoelectron spectroscopy indicates that the crystalline phase of these films has the composition Co9S8. The nodes of the metal-organic framework (MOF) NU-1000 were then selectively functionalized with cobalt sulfide via ALD in MOFs (AIM). Spectroscopic techniques confirm uniform deposition of cobalt sulfide throughout the crystallites, with no loss in crystallinity or porosity. The resulting material, CoS-AIM, is catalytically active for selective hydrogenation of m-nitrophenol to m-aminophenol, and outperforms the analogous oxide AIM material (CoO-AIM) as well as an amorphous CoSx reference material. These results reveal AIM to be an effective method of incorporating high surface area and catalytically active cobalt sulfide in metal-organic frameworks.

The effect of adding hydrogen to methane on the emission and heat transfer characteristics of a laminar diffusion flame was investigated. The total input thermal energy for each test was kept constant. The results showed that adding hydrogen increased the temperature, decreased the flame length, and significantly increased the soot-free length fraction. CO and CO2 emission decreased with the addition of hydrogen. The more efficient oxidation of CO to CO2 at higher hydrogen fractions was the main contributor to the reduction of CO, whereas decreased carbon input was the dominant factor for the reduction of CO2. The NOx emission increased owing to the increase of prompt, thermal NOx formation and NNH pathway. The ratio of radiative heat flux to total heat flux decreased, and the radiative heat flux did not exceed 5% of the total heat flux. The addition of hydrogen improved the total heat flux by approximately 20%.

Thermal radiation is an important mode in combustion and plays a key role in improving energy efficiency and reducing the formation of pollutants in industrial combustion systems. This paper describes the effects of oxygen concentration and fuel (methane and propane) jet velocity on thermal radiation in turbulent diffusion flames via numerical evaluation, using a detailed gas-phase reaction mechanism consisting of 36 species and 219 elementary reactions with the discrete ordinates method. The predictions show close agreement with the experimental results in literature. Specifically, the radiative heat transfer flux and radiation fraction of propane flames were larger than those of methane flames at the same input power because of the increased soot yield in propane flames. In both methane and propane flames, thermal radiation generally increased with oxygen concentration, while at higher oxygen concentrations the degree of radiation increase was lower. Because of the promotion of soot oxidation at higher fuel velocities, the radiant fractions were lower than at lower fuel velocities.

Modeling of particulate or thin-layer drying of materials is necessary to understand the fundamental transport mechanism and a prerequisite to successfully simulate or scale up the whole process for optimization or control of the operating conditions. Simple models with a reasonable physical meaning are effective for engineering purposes. Thin-layer drying of green peas was carried out in a fluidized bed with a newly developed slotted gas distributor. Based on the reaction engineering approach, a drying model of green peas was well established, in which relative activation energy (ΔEv/ΔEv,b) was correlated with reduced moisture content (X − Xb) at a drying air temperature of 80°C. The drying kinetics of green peas was discussed in terms of activation energy. In addition, activation energy based on a simplified material surface temperature profile was recalculated to evaluate the temperature sensitivity to the model establishment.

Two new UiO-68 type of Zr-MOFs featuring redox non-innocent catechol-based linkers of different redox activities have been synthesized through a de novo mixed-linker strategy. Metalation of the MOFs with Cu(II) precursors triggers the reduction of Cu(II) by the phenyl-catechol groups to Cu(I) with the concomitant formation of semiquinone radicals as evidenced by EPR and XPS characterization. The MOF-supported catalysts are selective toward the allylic oxidation of cyclohexene and it is found that the presence of in situ-generated Cu(I) species exhibits enhanced catalytic activity as compared to a similar MOF with Cu(II) metalated naphthalenyl-dihydroxy groups. This work unveils the importance of metal-support redox interactions in the catalytic activity of MOF-supported catalysts which are not easily accessible in traditional metal oxide supports.

Few-atom cobalt-oxide clusters, when dispersed on a Zr-based metal–organic framework (MOF) NU-1000, have been shown to be active for the oxidative dehydrogenation (ODH) of propane at low temperatures (

Activated carbons were produced from walnut shell by fast activation with H3PO4in a spouted bed, and the influence of particles fluidization had been investigated. Experimental results showed that walnut shell particles with higher H3PO4impregnation ratios would be agglomerated in spouted bed, and difficult to fluidize. Therefore, an amount of quartz sands were added to assist fluidization of H3PO4impregnated walnut shell particles. The BET surface area of activated carbon prepared under fluidization would be obviously increased with H3PO4impregnation ratio, reaching 1549.6 m2/g for the mass ratio of H3PO4to walnut shell particles of 2 and activation temperature of 700°C. Meanwhile, both of the micro- and meso- pore volumes were increased. In addition, fluidization of particles had very little influence on activated carbon surface functional groups forming. It was found that the activated carbons contained more carbonyl groups (C = O), carboxyl groups (COOH) and some P-containing functional group.

Two kinds of pinewood sawdust activated carbon adsorbents were prepared by fast activation with H

NU-1000, a mesoporous metal–organic framework (MOF) featuring hexazirconium oxide nodes and 3 nm wide channels, was infiltrated with a reactive dicobalt complex to install dicobalt active sites onto the MOF nodes. The anchoring of the dicobalt complex onto NU-1000 occurred with a nearly ideal stoichiometry of one bimetallic complex per node and with the cobalt evenly distributed throughout the MOF particle. To access thermally robust multimetallic sites on an all-inorganic support, the modified NU-1000 materials containing either the dicobalt complex, or an analogous cobalt–aluminum species, were nanocast with silica. The resulting materials feature Co2or Co–Al bimetallated hexazirconium oxide clusters within a silica matrix. The cobalt-containing materials are competent catalysts for the selective oxidation of benzyl alcohol to benzaldehyde. Catalytic activity depends on the number of cobalt ions per node, but does not vary significantly between the NU-1000 and silica supports. Hence, the multimetallic oxide clusters remain site-isolated and substrate-accessible within the nanocast materials.

Correction for ‘Atomic layer deposition of Cu(i) oxide films using Cu(ii) bis(dimethylamino-2-propoxide) and water’ by J. R. Avila, et al., Dalton Trans., 2017, DOI: 10.1039/c6dt02572b.

Acidulant encapsulation is used to prevent the unwanted acid hydrolysis of other ingredients in food industry. It is preferred to efficiently solidify the molten coatings on acidulant particles. In this article, a molten lipid was atomized in a fluidized bed of cold citric acid powder for the production of encapsulated acidulant. The effect of lipid-to-citric acid mass ratio and atomization pressure on the size distribution of encapsulated particles was investigated. The median particle size (D50) increases with lipid content, and fine particles were reduced with lipid encapsulation. The surface morphology of lipid-encapsulated citric acid particles was studied by scanning electron micrograph to gain insight into the possible encapsulation mechanism. The encapsulation efficiency increases with the lipid-to-citric acid mass ratio.

Drying characteristics of soybeans under different microwave (MW) processing schemes were studied in regard to energy aspects. For drying in a single microwave power density, the experiments were carried out at a constant MW output power throughout the process. It was found that the drying rate is enhanced together with reduced energy consumption at higher single power density, but the soybean cracking ratio is increased gradually from 2 % to 40 % when the power density was changed from 0.2 W/g to 0.8 W/g. Efforts were made to reach a compromise between the drying rate and dried soybean quality by varying the MW power density in several steps overall the drying process, but soybean cracking occurred at a higher ratio due to the fluctuation of drying rate. Microwave drying of soybeans under the power density less than 0.2 W/g with slow and stable drying rate can achieve the soybean cracking ratio controlled within 5 % and lower energy consumption.

Ni(II) ions have been deposited on the Zr6 nodes of a metal-organic framework (MOF), UiO-66, via an ALD-like process (ALD = atomic layer deposition). By varying the number of ALD cycles, three Ni-decorated UiO-66 materials were synthesized. A suite of physical methods has been used to characterize these materials, indicating structural and high-surface-area features of the parent MOF are retained. Elemental analysis via X-ray photoelectron spectroscopy (XPS) indicates that the anchored Ni ions are mainly on surface and near-surface MOF defect sites. Upon activation, all three materials are catalytic for ethylene hydrogenation, but their catalytic activities significantly vary, with the largest clusters displaying the highest per-nickel-atom activity. The study highlights the ease and effectiveness ALD in MOFs (AIM) for synthesizing, specifically, UiO-66-supported NiyOx catalysts.

Metal-organic frameworks (MOFs) are periodic, hybrid, atomically well-defined porous materials that typically form by self-assembly and consist of inorganic nodes (metal ions or clusters) and multitopic organic linkers. MOFs as a whole offer many intriguing properties, including ultrahigh porosity, tunable chemical functionality, and low density. These properties point to numerous potential applications, including gas storage, chemical separations, catalysis, light harvesting, and chemical sensing, to name a few. Reticular chemistry, or the linking of molecular building blocks into predetermined network structures, has been employed to synthesize thousands of MOFs. Given the vast library of candidate nodes and linkers, the number of potentially synthetically accessible MOFs is enormous. Nevertheless, a powerful complementary approach to obtain specific structures with desired chemical functionality is to modify known MOFs after synthesis. This approach is particularly useful when incorporation of particular chemical functionalities via direct synthesis is challenging or impossible. The challenges may stem from limited stability or solubility of precursors, unwanted secondary reactivity of precursors, or incompatibility of functional groups with the conditions needed for direct synthesis. MOFs can be postsynthetically modified by replacing the metal nodes and/or organic linkers or via functionalization of the metal nodes and/or organic linkers. Here we describe some of our efforts toward the development and application of postsynthetic strategies for imparting desired chemical functionalities in MOFs of known topology. The techniques include methods for functionalizing MOF nodes, i.e., solvent-assisted ligand incorporation (SALI) and atomic layer deposition in MOFs (AIM) as well as a method to replace structural linkers, termed solvent-assisted linker exchange (SALE), also known as postsynthethic exchange (PSE). For each functionalization strategy, we first describe its chemical basis along with the requirements for its successful implementation. We then present a small number of examples, with an emphasis on those that (a) convey the underlying concepts and/or (b) lead to functional structures (e.g., catalysts) that would be difficult or impossible to access via direct routes. The examples, however, are only illustrative, and a significant body of work exists from both our lab and others, especially for the SALE/PSE strategy. We refer readers to the papers cited and to the references therein. More exciting, in our view, will be new examples and new applications of the functionalization strategies-especially applications made possible by creatively combining the strategies. Underexplored (again, in our view) are implementations that impart electrical conductivity, enable increasingly selective chemical sensing, or facilitate cascade catalysis. It will be interesting to see where these strategies and others take this compelling field over the next few years.

In regression analysis, there are two main aims: interpretation and prediction, which can be also applied in building performance analysis. Interpretation is used to understand the relationship between input parameters and building energy performance (also called sensitivity analysis), whereas prediction is used to create a reliable energy model to estimate building energy consumption. This article explores the implementation of a distribution-free bootstrap method for these two purposes. The bootstrap is a resampling method that enables assessment of the accuracy of an estimator by random sampling with replacement from an original dataset. An office building is used as a case study to demonstrate the application of this method in assessing building thermal performance. The results indicate that the probabilistic sensitivity analysis incorporating the bootstrap approach provides valuable insights into the variations in sensitivity indicators, which are not available from typical deterministic sensitivity analysis. The single point values from deterministic methods may lead to misleading prioritization of energy saving measures because they do not provide the distributions of sensitivity indicators. Information on prediction errors obtained from the bootstrap method can facilitate the selection of an appropriate building energy metamodel to more accurately predict the energy consumption of buildings, compared with the traditional one-time data splitting method (also called holdout cross-validation method), which partitions the data into a training set and a test set.

One of main characteristics for building energy in urban environment is spatially distributed. Both electricity and gas per dwelling in London have positive spatial autocorrelation, which indicates that neighbourhoods tend to cluster together with similar energy use. More importantly, when applying regression analysis, the residuals from standard linear energy models may also have spatial autocorrelation, which makes statistical inference more difficult. Therefore, it is important to consider spatial effects in analysing energy consumption patterns of buildings in urban settings. This paper applies OLS (ordinary least squares) and spatial regression models to investigate the relationship between council tax evaluation bands and domestic energy consumption in London. A significant correlation was found between the number of properties in each council tax band and the corresponding energy use. Based on both statistical and theoretical analysis, the SEM (spatial error models) are more appropriate in this study than the spatial lag models. The simulation results indicate the SEM can take the spatial correlation into account by decomposing the OLS original error terms in regression analysis. The general trend is that both electricity and gas consumption per dwelling would increase from the lower to higher council tax bands.

Non-uniform heating is a major issue in microwave applications, mainly due to inherently uneven distribution of electromagnetic energy in the microwave applicator. In this work, our aim is to improve electric field distribution uniformity by utilizing microwave reflection from electrically conductive beads placed in the microwave oven. The effects of position, size, and number of electrically conductive beads on the electric field distribution were numerically investigated, and validated through water-load experiments in the cavity. It is found that uniform electric field distribution was realized to some extent by appropriate placement of electrically conductive beads; meanwhile, average electric field intensity in the microwave oven was increased.

Liposomes loaded with the rhenium compound (bis-dimethylsulfoxido-cis-tetrachlorodi-μ-pivalatodirhenium(III) (cis-Re2((CH3)3CCOO)2Cl4.2DMSO, I) and cisplatin in the molar ratio of 4:1 as well as those loaded only with I were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, dynamic light scattering and electronic absorption spectroscopy. The relative stability of liposomes loaded with I is reflected by a minimal change in the electronic absorption spectra over a period of 8 days whereas the stability of those loaded with both drugs is lower, which we ascribe to the formation of new Re-Pt species inside the liposomes. Furthermore, the investigations of the co-encapsulation effects on the anticancer activity of the Re-Pt system were undertaken. Importantly, the co-encapsulated liposomes exhibit synergistic or additive anticancer activities in vivo, e.g. introduction of these liposomes into tumor-bearing rats demonstrated their antianemic, nephro- and hepato-protecting effects. These liposomes, which are active in cancer treatment, protect the dirhenium compounds from hydrolysis and preserve the biological properties of the Re-Pt hybrid. This study reveals the importance of combined therapy in nanotechnology and medicine.

A new technique for spray drying of egg white was developed and termed as pulse combustion spray drying (PCSD) which uses high-temperature pulsating jets generated by the pulse combustor to atomize and dry the liquid feed simultaneously. The pilot-scale PCSD testing of egg white was conducted and the drying energy efficiency was evaluated. Selected product properties of the PCSD egg white powders were measured. It was found that compared with traditional spray drying, the PCSD process achieved a higher energy efficiency of 2,604 kJ/kg water evaporated and the PCSD powders had a superior surface characteristics, smaller mean particle diameter, and more homogeneous size distribution. Additionally, the egg white proteins and their foaming and gelling properties were protected well in the PCSD process. Experimental results showed that the PCSD technique is promising for drying of egg white and even other heat-sensitive food feeds.

Two new series of dirhodium(II,II) complexes cis-[Rh2(μ-DTolF)2(L)2][BF4]2 and cis-[Rh2(μ-F-form)2(L)2][BF4]2 were synthesized and fully characterized (DTolF = p-ditolylformamidinate, F-form = p-difluorobenzylformamidinate; L = the chelating diimine ligands dpq (dipyrido[3,2-f:2′,3′-h]quinoxaline), dppz (dipyrido[3,2-a:2′,3′-c]phenazine) and dppn (benzo[i]dipyrido[3,2-a:2′,3′-h]quinoxaline). The complexes undergo facile oxidation and exhibit directed ligand-to-ligand charge transfer (LLCT) excited states upon excitation from the corresponding formamidinate to the diimine ligand. Time-resolved studies reveal that the LLCT states decay with lifetimes that range from 16 to 100 ps and generate a longer-lived excited state. For complexes with dpq and dppz ligands, the longer-lived excited state, with lifetimes that range from 40 to 100 ns, has been assigned as 3MC (MC = metal-centered) arising from the Rh2(π*) → Rh2(σ*) transition. In the case of cis-[Rh2(μ-DTolF)2(dppn)2]2+ and cis-[Rh2(μ-F-form)2(dppn)2]2+, the dppn-centered 3ππ* excited state is observed from ∼10 ps to ∼2 ns, but following its decay, the 3MC state of each complex is observed with lifetimes of 2.4 and 3.0 μs, respectively. The long lifetimes observed for the dppn complexes is explained by a pre-equilibrium of the low-lying 3ππ* and 3MC states. The excited state oxidation potentials, E*ox(1LLCT), for the complexes are calculated to lie between −2.5 and −2.8 V vs. SCE and E*ox(3MC) ∼ −1.8 V vs. SCE. The 1LLCT excited states of the complexes are also good oxidizing agents, with E*red(1LLCT) ∼ +1.3 V vs. SCE, making them significantly better oxidizing and reducing agents than commonly used Ru(II) complexes.

In this paper, we study the existence of periodic solutions for a class of quadratic contact Hamiltonian system with a small parameter by averaging theory.We have proved that the quadratic contact Hamiltonian system has a stable periodic solution and an unstable periodic solution when the corresponding parameter is small enough.

The disposal of waste plastics is a major environmental issue all over the world. As an alternative to disposal that also adds value to the waste product, polycarbonate particles were used as model waste plastic material, mixed with sodium hydroxide and then pyrolyzed at 773 K to produce activated carbon. Activated carbon has numerous industrial applications, including use as adsorbents in adsorption heat pumps and several environmental applications. Activated carbon obtained upon pyrolysis was characterized by determining its adsorption capacity for liquid nitrogen and water vapor. The effects of the key process variables, i.e., chemical ratio and activation time, on micropore development and water adsorptivity were evaluated by response surface methodology. The quadratic models were found to be satisfactory in describing their performance. Based on the contour plots, activated carbon with a maxima of surface area and micropore volumes can be produced at an optimal level of chemical ratio along with longer activation time. The water adsorptivity generally has less difference at low relative pressures, but inflexion of water adsorptivity occurs at a relative pressure of P/P 0 ≈ 0.4. The optimized water adsorptivity in the operating pressure range of adsorption heat pumps (P/P 0 = 0.11–0.38) can exceed 0.24 kg/kg.

During drying, hydrodynamics of fluidized beds can vary due to moisture evaporation. It is of practical importance to quantify the fluidized bed hydrodynamics by analysis of pressure fluctuations, especially when drying cohesive materials. In this study, spent liquor from a fermentation process for the production of yeast was mixed with corn bran at different mass ratios, and used as the fluidizing material of various stickiness levels. Local bed pressure fluctuations and the dryer exhaust air temperature as well as relative humidity were monitored over the course of drying. The pressure fluctuation data were analyzed using statistical methods. The bed hydrodynamic behavior was interpreted in terms of the time-averaged bed-pressure drop and its standard deviation. The transition from channeling to uniform fluidization occurs when both the average pressure drop and the standard deviation vary little with time. Also, the average values of the bed-pressure drop within short periods in reference to the ideal ...

Developing structurally well-defined, supported oxide catalysts remains a significant challenge. Here, we report the grafting of Nb(V) oxide sites onto the nodes of the Zr-based metal organic framework (MOF) NU-1000 as a stable, well-defined catalyst support. Nb(V) oxide was deposited with loadings up to 1.6 mmol/g via two postsynthetic methods: atomic layer deposition in a MOF, and solution-phase grafting in a MOF. Difference envelope density measurements indicated that the two synthetic methods resulted in different local structures of the Nb(V) ions within NU-1000. Despite their high Nb(V) loadings, which were equivalent to >60% surface coverage, nearly all Nb(V) sites of the MOF-supported catalysts were active sites for alkene epoxidation, as confirmed by phenylphosphonic acid titration. The MOF-supported catalysts were more selective than the control Nb-ZrO2 catalyst for cyclohexene epoxidation with aqueous H2O2 and were far more active on a gravimetric basis.