Recent Progress on Stability and Passivation of Black Phosphorus

From a fundamental science perspective, black phosphorus (BP) is a canonical example of a material that possesses fascinating surface and electronic properties. It has extraordinary in‐plane anisotropic electrical, optical, and vibrational states, as well as a tunable band gap. However, instability of the surface due to chemical degradation in ambient conditions remains a major impediment to its prospective applications. Early studies were limited by the degradation of black phosphorous surfaces in air. Recently, several robust strategies have been developed to mitigate these issues, and these novel developments can potentially allow researchers to exploit the extraordinary properties of this material and devices made out of it. Here, the fundamental chemistry of BP degradation and the tremendous progress made to address this issue are extensively reviewed. Device performances of encapsulated BP are also compared with nonencapsulated BP. In addition, BP possesses sensitive anisotropic photophysical surface properties such as excitons, surface plasmons/phonons, and topologically protected and Dirac semi‐metallic surface states. Ambient degradation as well as any passivation method used to protect the surface could affect the intrinsic surface properties of BP. These properties and the extent of their modifications by both the degradation and passivation are reviewed.     

A Fuzzy-Stochastic Modeling Approach for Multiple Criteria Decision Analysis of Coupled Groundwater-Agricultural Systems

The complexity of water resources management increases when decisions about environmental and social issues are considered in addition to economic efficiency. Such complexities are further compounded by multiple uncertainties about the consequences of potential management decisions. In this paper, a new fuzzy-stochastic multiple criteria decision-making approach is proposed for water resources management in which a variety of criteria in terms of economic, environmental and social dimensions are identified and taken into account. The goal is to evaluate multiple conflicting criteria under uncertainties and to rank a set of management alternatives. The methodology uses a simulation-optimization water management model of a strongly interacting groundwater-agriculture system to enumerate criteria based on these bio-physical process interactions. Fuzzy and/or qualitative information regarding the decision-making process for which quantitative data is not available are evaluated in linguistic terms. Afterwards, Monte Carlo simulation is applied to combine these information and to generate a probabilistic decision matrix of management alternatives versus criteria in an uncertain environment. Based on this outcome, total performance values of the management alternatives are calculated using ordered weighted averaging. The proposed approach is applied to a real world example, where excessive groundwater withdrawal from the coastal aquifer for irrigated agriculture has resulted in saltwater intrusion, threatening the economical basis of farmers and associated societal impacts. The analysis has provided potential decision alternatives which can serve as a platform for negotiation and further exploration. Furthermore, sensitivity of different inputs to resulting rankings is investigated. It is found that decision makers’ risk aversion and risk taking attitude may yield different rankings. The presented approach suits to systematically quantify both probabilistic and fuzzy uncertainties associated with complex hydrosystems management.     

Effect of endogenous hydrogen utilization on improved methane production in an integrated microbial electrolysis cell and anaerobic digestion: Employing catalyzed stainless steel mesh cathode

Improving the production of methane,while maintaining a significant level of process stability,is the main challenge in the anaerobic digestion process.Recently,microbial electrolysis cell (MEC) has become a promising method for CO2 reduction produced during anaerobic digestion (AD) and leads to minimize the cost of biogas upgrading technology.In this study,the MEC-AD coupled reactor was used to generate and utilize the endogenous hydrogen by employing biocompatible electrodeposited cobalt-phosphate as catalysts to improve the performance of stainless steel mesh and carbon cloth electrodes.In addition,the modified version of ADM1 model (ADM1da) was used to simulate the process.The result indicated that the MEC-AD coupled reactor can improve the CH4 yield and production rate significantly.The CH4 yield was enhanced with an average of 48％ higher than the control.The CH4 production rate was also increased 1.65 times due to the utilization of endogenous hydrogen.The specific yield,flow rate,content of CH4,and pH value were the variables that the model was best at predicting (with indexes of agreement:0.960/0.941,0.682/0.696,0.881/0.865,and 0.764/0.743) of the process with SS-meshes 80/SS-meshes 200,respectively.Employing the catalyzed SS mesh cathode,in the MEC-AD coupled reactor,could be an effective approach to generate and facilitate the utilization of endogenous hydrogen in anaerobic digestion of CH4 production technology,which is a promising and feasible method to scale up to the industrial level.     

Heterogeneous catalysis for biodiesel production from Jatropha curcas oil (JCO)

This work focuses on the development of heterogeneous catalysts for biodiesel production from high free fatty acid (FFA) containing Jatropha curcas oil (JCO). Solid base and acid catalysts were prepared and tested for transesterification in a batch reactor under mild reaction conditions. Mixtures of solid base and acid catalysts were also tested for single-step simultaneous esterification and transesterification. More soap formation was found to be the main problem for calcium oxide (CaO) and lithium doped calcium oxide (Li-CaO) catalysts during the reaction of jatropha oil and methanol than for the rapeseed oil (RSO). CaO with Li doping showed increased conversion to biodiesel than bare CaO as a catalyst. La₂O₃/ZnO, La₂O₃/Al₂O₃ and La_0.1Ca_0.9MnO₃ catalysts were also tested and among them La₂O₃-ZnO showed higher activity. Mixture of solid base catalysts (CaO and Li-CaO) and solid acid catalyst (Fe₂(SO₄)₃) were found to give complete conversion to biodiesel in a single-step simultaneous esterification and transesterification process.     

Homogeneous combustion of fuel-lean H2/O2/N2 mixtures over platinum at elevated pressures and preheats

The gas-phase combustion of H₂/O₂/N₂ mixtures over platinum was investigated experimentally and numerically at fuel-lean equivalence ratios up to 0.30, pressures up to 15 bar and preheats up to 790 K. In situ 1-D spontaneous Raman measurements of major species concentrations and 2-D laser induced fluorescence (LIF) of the OH radical were applied in an optically accessible channel-flow catalytic reactor, leading to the assessment of the underlying heterogeneous (catalytic) and homogeneous (gas-phase) combustion processes. Simulations were carried out with a 2-D elliptic code that included elementary hetero-/homogeneous chemical reaction schemes and detailed transport. Measurements and predictions have shown that as pressure increased above 10 bar the preheat requirements for significant gas-phase hydrogen conversion raised appreciably, and for p = 15 bar (a pressure relevant for gas turbines) even the highest investigated preheats were inadequate to initiate considerable gas-phase conversion. Simulations in channels with practical geometrical confinements of 1 mm indicated that gas-phase combustion was altogether suppressed at atmospheric pressure, wall temperatures as high as 1350 K and preheats up to 773 K. While homogeneous ignition chemistry controlled gaseous combustion at atmospheric pressure, flame propagation characteristics dictated the strength of homogeneous combustion at the highest investigated pressures. The decrease in laminar burning rates for p ? 8 bar led to a push of the gaseous reaction zone close to the channel wall, to a subsequent leakage of hydrogen through the gaseous reaction zone, and finally to catalytic conversion of the escaped fuel at the channel walls. Parametric studies delineated the operating conditions and geometrical confinements under which gas-phase conversion of hydrogen could not be ignored in numerical modeling of catalytic combustion.     

Symmetry complementarity-guided design of anthrax toxin inhibitors based on β-cyclodextrin: Synthesis and relative activities of face-selective functionalized polycationic clusters

Three new series of potential anthrax toxin inhibitors based on the β‐cyclodextrin (βCD) scaffold were developed by exploiting face‐selective Cu^I‐catalyzed azide–alkyne 1,3‐cycloadditions, amine–isothiocyanate coupling, and allyl group hydroboration–oxidation/hydroxy → amine replacement reactions. The molecular design follows the “symmetry–complementarity” concept between homogeneously functionalized polycationic βCD derivatives and protective antigen (PA), a component of anthrax toxin known to form C₇‐symmetric pores on the cell membrane used by lethal and edema factors to gain access to the cytosol. The synthesis and antitoxin activity of a collection of βCD derivatives differing in the number, arrangement, and face location of the cationic elements are reported herein. These results set the basis for a structure–activity relationship development program of new candidates to combat the anthrax threat.     

Quantifying and mapping ecosystem services supplies and demands: a review of remote sensing applications

Ecosystems provide services necessary for the livelihoods and well-being of people. Quantifying and mapping supplies and demands of ecosystem services is essential for continuous monitoring of such services to support decision-making. Area-wide and spatially explicit mapping of ecosystem services based on extensive ground surveys is restricted to local scales and limited due to high costs. In contrast, remote sensing provides reliable area-wide data for quantifying and mapping ecosystem services at comparatively low costs, and with the option of fast, frequent, and continuous observations for monitoring. In this paper, we review relevant remote sensing systems, sensor types, and methods applicable in quantifying selected provisioning and regulatory services. Furthermore, opportunities, challenges, and future prospects in using remote sensing for supporting ecosystem services' quantification and mapping are discussed.     

Comprehensive two-dimensional field-flow fractionation-liquid chromatography in the analysis of large molecules

A novel, comprehensive two-dimensional asymmetric field-flow fractionation-liquid chromatographic system is described (AsFlFFF-RPLC). The interface is based on a switching valve, and the whole sample is analyzed in both dimensions. The system proved to be repeatable and quantitative in the characterization of egg white proteins. Four peaks at 4, 5.5-6.0, 7.5-8.0, and 10.0-11.0 nm, and corresponding to lysozyme, ovalbumin, transferrin, and a dimer of transferrin, were obtained in the AsFlFFF first-dimension system. Lysozyme also produced an additional peak, which overlapped with ovalbumin. Twelve compounds were separated in the LC second-dimension system. Identifications were made with the help of standards (ovalbumin, ovotransferrin, lysozyme) and by comparison of the peak areas, particle sizes, and retention data with values given in the literature. The effect of heat on egg white denaturation was studied, and the unfolding of peptide bonds of the protein was found to be pronounced when the sample was heated in phosphate solution.     

Quality of life in elderly patients with COPD: measurement and predictive factors

OBJECTIVE: To examine the interrater reliability and completion time of the Functional Assessment Measure, which is the Functional Independence Measure (FIM) plus additional items (FIM+FAM). DESIGN: Interrater reliability study. SETTING: Inpatient rehabilitation units of a postacute care brain injury rehabilitation program. PATIENTS: A convenience sample of 53 extremely severely impaired adult survivors of traumatic brain injuries (40 men, 13 women, mean age 38yrs). MAIN OUTCOME MEASURES: Treatment team members' ratings of the 30 FIM +FAM items, and time taken to complete the FIM+FAM. RESULTS: Intraclass Correlation Coefficients (ICCs) were within the good to excellent range (ICC > .60) for 29 of 30 items and for all subscales except psychosocial adjustment. Higher mean ICC values were obtained for motor domain items than for cognitive/psychosocial domain items. Treatment teams became progressively faster over a 12-week period in completing the FIM+FAM. The generally good to excellent range interrater reliability found in this study helps support the use of the FIM+FAM in rehabilitation settings. Further support was obtained for the finding that motor items are more reliable than cognitive and psychosocial items. Administration of the FIM+FAM can be done in a timely manner in a rehabilitation setting.