Viscosity model of deep eutectic solvents from group contribution method

Deep eutectic solvents (DESs), a novel category of sustainable solvents, are expected to achieve the design of the chemical processes without utilizing or generating harmful chemicals. In this work, based on the mathematical model inspired by the transition state theory, the group contribution method is used to accurately predict the viscosity of DESs. The model is constrained by Eyring rate theory and hard sphere free volume theory. A dataset of 2229 experimental viscosity data points of 183 DESs from literature is used to determine the model parameters and subsequently verify the model. The rules introduced by this model are simple and easy to follow. The results show that the proposed model is capable to predict the viscosity of DESs with very high accuracy, using only temperature and composition as inputs. The average absolute relative deviations (AARDs) of the model are 8.12% and 8.64% over the training and test sets, respectively, and the maximum ARD is 34.63%. Therefore, the as-proposed model can be considered a highly reliable tool for predicting the viscosity of DESs when experimental data are absent. It will provide useful guidance for the synthesis of DESs with specific viscosity to meet different application requirements and promote their industrial-scale implementation.     

初加工对不同产地小粒咖啡活性成分及风味酶活性的影响

目的 为探究初加工对不同产地咖啡活性成分和风味酶活性的影响。方法 采用比色法测定生豆及其副产物中多酚、黄酮、多糖含量。采用酶活性检测试剂盒测定其过氧化氢酶（catalase，CAT）、脂氧合酶（lipoxygenase，LOX）、β-葡萄糖苷酶（β-glucosidase，β-GC）和脂肪酶（lipase，LPS）活性。结果 结果表明，多酚、黄酮含量总体来看产地一高于产地二，其中产地一所有生豆样品多酚含量均大于40 mg/g；黄酮含量均大于4 mg/g，蜜处理生豆黄酮含量最高达到了5.40 mg/g；且生豆样品的多酚、黄酮含量均比副产物的多。多糖含量最高为产地二的日晒果皮，为28.23 mg/g。此外，产地一生豆样品的CAT、β-GC和LPS总体活性强于产地二；产地一副产物的β-GC和LOX整体活性高于产地二，CAT和LPS整体活性相反。结论 初加工对生豆及副产物样品的活性成分和风味酶活性均有影响，但是影响程度不一。从健康效益和最终获得更多的风味物质的角度来说，产地一的样品略优于产地二的样品。     

Using silicone passive samplers to detect polycyclic aromatic hydrocarbons from wildfires in streams and potential acute effects for invertebrate communities

Silicone rubber passive samplers spiked with 4 deuterated performance reference compounds were deployed for 29-33 days to estimate the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in 9 streams in Victoria, Australia, following a wildfire. Silicone rubber strips of 2 thicknesses were used to obtain information on the status of uptake of the chemicals of interest at retrieval. In addition, we monitored the stream macroinvertebrate community for potential effects of PAHs or other fire organics. All selected PAHs were detected in the passive samplers and the sampling rates ranged from 0.5 to 50 L/day significantly varying between sites but not compounds, presumably due to differences in current velocity. The estimated water concentrations were 0.1-10 ng/L for total PAHs with phenanthrene, pyrene and fluoranthene accounting for 91% of the total concentration. All PAHs were a factor of 1000 or more below the reported 48-h median lethal concentrations (48-h LC50) for Daphnia magna. Two sites located closest to the fires exhibited elevated concentrations compared to the other sites and the passive samplers in these sites remained in the integrative uptake regime for all compounds, suggesting precipitation-associated PAH input. No acute toxic effects of PAHs or other fire organics on the invertebrate community were detected using a biotic index for organic toxicants (SPEAR), whereas a non-specific biotic index (SIGNAL) decreased in two sites indicating impacts from changes in other environmental parameters. We conclude (1) that silicone-based passive samplers with two different area-to-volume ratios represent a promising tool for determining organic toxicants and (2) that PAHs from wildfires are unlikely to be a common main cause for fire-related ecological effects in streams adjacent to burnt regions.     

Pre-stack basis pursuit seismic inversion for brittleness of shale

Brittleness of rock plays a significant role in exploration and development of shale gas reservoirs. Young’s modulus and Poisson’s ratio are the key parameters for evaluating the rock brittleness in shale gas exploration because their combination relationship can quantitatively characterize the rock brittleness. The highvalue anomaly of Young’s modulus and the low-value anomaly of Poisson’s ratio represent high brittleness of shale. The technique of pre-stack amplitude variation with angle inversion allows geoscientists to estimate Young’s modulus and Poisson’s ratio from seismic data. A model constrained basis pursuit inversion method is proposed for stably estimating Young’s modulus and Poisson’s ratio. Test results of synthetic gather data show that Young’s modulus and Poisson’s ratio can be estimated reasonably. With the novel method, the inverted Young’s modulus and Poisson’s ratio of real field data focus the layer boundaries better, which is helpful for us to evaluate the brittleness of shale gas reservoirs. The results of brittleness evaluation show a good agreement with the results of well interpretation.     

Activating AIN thin film by introducing Co nanoparticles as a new anode material for thin-film lithium batteries

AIN/Co nanocomposite thin films were fabricated by pulsed laser deposition and investigated as new anode materials for lithium-ion batteries for the first time.The combination of electrochemically inactive AlN and Co in nanometer scale boosted the electrochemical performance of the thin films surprisingly.A high reversible capacity of 555 mAh·g~(-1) after 100 discharge-charge cycles at a current density of 500 mA·g~(-1) is obtained for the AIN/Co nanocomposite thin films,and 372 mAh·g~(-1)can be retained at a high rate up to 16 C,exhibiting promising cycle stability and rate capability.The electrochemical reaction mechanism study reveals that Co nanoparticles could not only provide high electronic conductivity for the thin films,which facilitate the thorough decomposition of AIN in the initial discharge process,but also react with Li_3 N to form a new species Co_2 N during charge process,thus ensuring large capacity and high reversibility of AIN/Co nanocomposite thin films in subsequent cycles.This study provides a new perspective to design advanced electrode materials for lithium-ion batteries.     

Comparison of ASTM saturation techniques for measuring the permeable porosity of concrete

The aim of this study is to compare the efficacy of the ASTM saturation techniques for measuring the permeable porosity of concrete. The permeable porosity of two ordinary concretes has been determined by three ASTM saturation techniques, namely cold-water saturation (CWS), boiling-water saturation (BWS) and vacuum saturation (VAS). The concretes were prepared with the water-cement ratios of 0.50 and 0.60, and tested at ages of 7 and 28 days. Based on the test results of permeable porosity, the efficiency of the saturation techniques has been compared. In addition, the compressive strength of concretes was determined to justify the results of permeable porosity. The slump test was also performed to observe the workability. The overall experimental results reveal that vacuum saturation technique is more efficient than cold-water or boiling-water saturation and therefore this technique should be recommended for measuring the permeable porosity of concrete.     

Landslide assessment for land use planning and infrastructure management in the Paphos District of Cyprus

The Paphos District has been described as one of the most landslide-prone areas of Cyprus, with landslides impacting villages, roads and other infrastructure. With increasing levels of development and investment in infrastructure, Cypriot authorities are investigating ways to assess landslide susceptibility, hazard and risk for planning purposes. A 2-year project has catalogued over 1,840 landslides, investigated the spatial distribution of key landslide attributes, and used the results to develop maps of landslide susceptibility across large areas of the Paphos District. To gain a better understanding of the materials and failure mechanisms involved, 20 of these landslides were selected for further study, including engineering geological mapping, ground investigation, laboratory testing, development of ground models and slope stability analysis at specific locations. The results enabled soil parameters to be reviewed, thus strengthening the interpretations derived from field observations. The use of the mapping outputs is discussed in terms of planning and engineering applications and recommendations are made for strengthening and expanding the landslide database.     

Investigations into the thermodynamics of polypeptide interaction with nonpolar ligands

In this paper, we describe a general procedure to evaluate the thermodynamics of the interaction between polypeptides and hydrophobic ligands in the presence of aquo-organic solvent mixtures. These studies address experimental requirements for the determination of the linear free energy relationships, derivation of partition coefficients or other extrathermodynamic parameters such as contact areas, or assessment of the conformational changes that may occur when polypeptides or proteins interact with immobilized nonpolar ligands. Not unexpectedly from thermodynamic arguments, the trends and magnitudes of free energy parameters, such as the enthalpy of association, as previously derived in many studies from gradient elution reversed-phase high-performance liquid chromatographic (RP-HPLC) measurements are often different from the data for the same parameters derived from equilibrium binding or microcalorimetric determinations. To reconcile these divergencies and to more closely examine the thermodynamic basis of the interaction of polypeptides with nonpolar ligands, the dependency of the logarithmic capacity factor, ln k', on temperature, T, for several polypeptides (bombesin, beta-endorphin, glucagon) have been investigated using a n-butylsilica and acetonitrile-water or methanol-water mixtures of defined solvent compositions. With low-pH, acetonitrile-water mixtures, the van't Hoff plots, i.e., the plots of ln k' versus 1/T, were nonlinear over the range of T = 278-358 K, although within a narrow temperature range, e.g., from T = 278-308 K, the experimental data for these polypeptides could be approximated by a linear relationship. This nonclassical van't Hoff behavior was associated with interactive processes that involved temperature-dependent enthalpic, entropic, and heat capacity changes. In contrast, with low-pH, methanol-water mixtures, the van't Hoff plots showed dependencies that were essentially linear over the range of T = 278-358 K. The slopes of the van't Hoff plots with acetonitrile-water and methanol-water mixtures at a defined T value and solvent composition were significantly larger than those found for the corresponding experiments carried out under gradient elution RP-HPLC conditions. From these plots of ln k' versus 1/T, the changes in the apparent enthalpy of association (delta H++assoc) and the apparent entropy of association (delta S++assoc) for the interaction of these polypeptides with the solvated n-butyl ligands at different T and solvent compositions have been determined. For these polypeptides, both delta H++assoc and delta S++assoc exhibited linear dependencies on the volume fraction, phi, of the organic solvent over a narrow range of T, but the slopes of these plots were dependent on the T range examined. The dependencies of the slope term, S, and the intercept term, ln ko, derived from the plots of ln k' versus phi as a function of T, have also been investigated. A new relationship linking the S values with delta H++assoc and delta S++assoc as a function of T and phi has been derived and validated. In addition, the relationship between S, delta H++assoc, delta S++assoc, the apparent change in heat capacity, delta C++assoc, and the accessible surface area, delta Atot, of these polypeptides has been examined, thus providing a linkage of these thermodynamic and extrathermodynamic parameters to the partition coefficient, P, and the molecular properties of these polypeptides. The results confirm that entropy-enthalpy compensation effects participate in the interaction of polypeptides with hydrophobic ligands. This investigation has confirmed that the use of solvent-water mixtures of defined composition, rather than the more convenient practice of using gradient elution methods, is essential if thermodynamically consistent values of the binding affinities and partition coefficients are to be quantitatively derived. (ABSTRACT TRUNCATED)