Liquid deposition modification of nano-ZSM-5 zeolite and catalytic performance in aromatization of Hexene-1

The Olefin aromatization is an important method for the upgrade of catalytic cracking (FCC) gasoline and production of fuel oil with high octane number. The nano-ZSM-5 zeolite was synthesized via a seed-induced method, a series of modified nano-ZSM-5 zeolite samples with different Ga deposition amount were prepared by Ga liquid deposition method. The XRD, N2 physical adsorption, SEM, TEM, XPS, H2-TPR and Py-IR measurements were used to characterize the morphology, textural properties and acidity of the modified ZSM-5 zeolites. The catalytic performance of the Hexene-1 aromatization was evaluated on a fixed-bed microreactor. The effects of Ga modification on the physicochemical and catalytic performance of nano-ZSM-5 zeolites were investigated. The Ga species in the modified nano-ZSM-5 zeolites mainly exist as the form of Ga2O3 and GaO+, which provide strong Lewis acid sites. The aromatics selectivity over Ga modified nano-ZSM-5 zeolite in the Hexene-1 aromatization was significantly increased, which could be attributed to the improvement of the dehydrogenation activity. The selectivity for aromatics over the Ga4.2/NZ5 catalyst with suitable Ga deposition amount reached 55.4%.

Good Agreement Between Modeled and Measured Sulfur and Nitrogen Deposition in Europe, in Spite of Marked Differences in Some Sites

Atmospheric nitrogen and sulfur deposition is an important effect of atmospheric pollution and may affect forest ecosystems positively, for example enhancing tree growth, or negatively, for example causing acidification, eutrophication, cation depletion in soil or nutritional imbalances in trees. To assess and design measures to reduce the negative impacts of deposition, a good estimate of the deposition amount is needed, either by direct measurement or by modeling. In order to evaluate the precision of both approaches and to identify possible improvements, we compared the deposition estimates obtained using an Eulerian model with the measurements performed by two large independent networks covering most of Europe. The results are in good agreement (bias <25%) for sulfate and nitrate open field deposition, while larger differences are more evident for ammonium deposition, likely due to the greater influence of local ammonia sources. Modeled sulfur total deposition compares well with throughfall deposition measured in forest plots, while the estimate of nitrogen deposition is affected by the tree canopy. The geographical distribution of pollutant deposition and of outlier sites where model and measurements show larger differences are discussed.

Leaf surface characteristics affect the deposition and distribution of droplets in rice (Oryza sativa L.)

We studied the effects of leaf surface characteristics on canopy droplet behaviour using two rice cultivars with similar leaf shapes but significantly different leaf surface characteristics: Jia58 (glabrous rice; smooth leaf surface and no burrs) and Yongyou12 (hairy-leaved rice; rough leaf surface covered with burrs). The plants were subjected to spray tests with different spray pressures and nozzle apertures. The results showed that the deposition amount per unit leaf area was significantly higher in the Yongyou12 canopy than in the Jia58 canopy. The diameter, volume median diameter, number median diameter, and coverage of droplets were significantly higher in Yongyou12 than in Jia58, while the coverage density of droplets was significantly lower. The proportion of small droplets of Jia58 is higher than that of Yongyou12. Thus, a larger amount of large-sized droplets could retain on the leaf surface of hairy-leaved rice, and a larger number of small-sized droplets were retained on the leaf surface of glabrous rice. Smaller pressure and larger flow nozzle were conducive to the retention of the Jia58, while Yongyou12 required larger pressure and larger flow nozzles. Ultrastructural analyses revealed that the leaf surface of glabrous rice had no trichomes and more wax than hairy-leaved rice, and the critical surface tension was lower, resulting in the retention of mainly small droplets on its leaf surface and a lower deposition amount. Therefore, in order to increase the deposition of pesticide droplets on the leaf surface in production, glabrous rice should choose nozzles with smaller spray pressure and large flow rate.

Photocatalytic and Electrocatalytic Properties of Cu-Loaded ZIF-67-Derivatized Bean Sprout-Like Co-TiO2/Ti Nanostructures

ZIF-derivatized catalysts have shown high potential in catalysis. Herein, bean sprout-like Co-TiO2/Ti nanostructures were first synthesized by thermal treatment at 800 °C under Ar-flow conditions using sacrificial ZIF-67 templated on Ti sheets. It was observed that ZIF-67 on Ti sheets started to thermally decompose at around 350 °C and was converted to the cubic phase Co3O4. The head of the bean sprout structure was observed to be Co3O4, while the stem showed a crystal structure of rutile TiO2 grown from the metallic Ti support. Cu sputter-deposited Co-TiO2/Ti nanostructures were also prepared for photocatalytic and electrocatalytic CO2 reduction performances, as well as electrochemical oxygen reaction (OER). Gas chromatography results after photocatalytic CO2 reduction showed that CH3OH, CO and CH4 were produced as major products with the highest MeOH selectivity of 64% and minor C2 compounds of C2H2, C2H4 and C2H6. For electrocatalytic CO2 reduction, CO, CH4 and C2H4 were meaningfully detected, but H2 was dominantly produced. The amounts were observed to be dependent on the Cu deposition amount. Electrochemical OER performances in 0.1 M KOH electrolyte exhibited onset overpotentials of 330–430 mV (vs. RHE) and Tafel slopes of 117–134 mV/dec that were dependent on Cu-loading thickness. The present unique results provide useful information for synthesis of bean sprout-like Co-TiO2/Ti hybrid nanostructures and their applications to CO2 reduction and electrochemical water splitting in energy and environmental fields.

Albumin Acts as a Lubricant on the Surface of Hydrogel and Silicone Hydrogel Contact Lenses

Feeling comfortable is the greatest concern for contact lens wearers, and it has been suggested that in vivo comfort could be corresponded to the in vitro friction coefficient of contact lenses. How tear albumin could affect the friction coefficient of silicone hydrogel and hydrogel contact lenses was analyzed by sliding a lens against a quartz glass in normal and extremely high concentration of albumin solution. Albumin deposition testing and surface roughness analysis were also conducted. The results showed that the friction coefficient of tested contact lenses did not correspond to both the albumin deposition amount and surface roughness, but we proposed a model of how albumin might act as a lubricant on the surface of some hydrogel and silicone hydrogel contact lenses. In conclusion, albumin provided lubrication for silicone hydrogel contact lenses regardless of albumin concentrations, while albumin only acted as a lubricant for hydrogel contact under normal concentration.

Independent Control Over Size and Surface Density of Droplet Epitaxial Nanostructures Using Ultra-Low Arsenic Fluxes

Modern and future nanoelectronic and nanophotonic applications require precise control of the size, shape and density of III-V quantum dots in order to predefine the characteristics of devices based on them. In this paper, we propose a new approach to control the size of nanostructures formed by droplet epitaxy. We reveal that it is possible to reduce the droplet volume independently of the growth temperature and deposition amount by exposing droplets to ultra-low group-V flux. We carry out a thorough study of the effect of arsenic pressure on the droplet characteristics and demonstrate that indium droplets with a large initial size (>100 nm) and a low surface density (<108 cm−2) are able to shrink to dimensions appropriate for quantum dot applications. Small droplets are found to be unstable and difficult to control, while larger droplets are more resistive to arsenic flux and can be reduced to stable, small-sized nanostructures (~30 nm). We demonstrate the growth conditions under which droplets transform into dots, ring and holes and describe a mechanism of this transformation depending on the ultra-low arsenic flux. Thus, we observe phenomena which significantly expand the capabilities of droplet epitaxy.

Reducing Spray Drift and Increasing Spreading Effect of the Thifluzamide Through the Use of Adjuvants and Nozzles

Spray drift, as a practical issue during Unmanned Aerial Vehicle (UAV) spraying, has a negative impact on the environment, and the use of air-induction nozzles or anti-drift adjuvants are the most common recommendations for reducing drift. To screen the adjuvants for favourable atomization performance and anti-drift effect, we evaluated the spray atomization performance of different adjuvants by the droplet size measurement system. From the wind tunnel results, we commented on the relationship among the atomization performance, drift distance and drift deposition, and determined the drift percentage of different nozzles and the surface tension of liquids with different adjuvants. The results showed that the addition of adjuvants would modify the distribution span S, ΦVol<150μm and the volume medium diameter D50; ΦVol<150μm and D50 of the Maifei treatment decreased and increased the most of all the treatments. There were negative correlations between the drift distance, D50 and percentage of drift amount. The adjuvants Maifei and the nozzle IDK120-015 significantly decreased the drift deposition amount. And the anti-drift effect of nozzle IDK120-015 plus Maifei was significantly stronger than that of other nozzles or adjuvants. In addition, the addition of adjuvants could significantly decrease the surface tension, especially for Maifei. These results suggest that the addition of Maifei is an effective way to reduce the spray drift for all nozzle types and lessen the surface tension. These data help to provide a theoretical basis for selecting suitable nozzles and adjuvants for plant protection UAVs.

Formation mechanism of zigzag patterned P(NIPAM-co-AA)/CuS composite microspheres by in situ biomimetic mineralization for morphology modulation

P(NIPAM-co-AA)/CuS composite microspheres with zigzag patterned surfaces were synthesized, and a mechanism for “the deformed shrinkage of the surface texture” was proposed. The surface morphology is sensitive to factors such as Ksp, pH, temperature, deposition amount, etc.

Modeling and Analysis of Iron Mass Transfer Behaviors in Supercritical Boiler Steam-Water System

Iron (Fe) concentration is a crucial parameter for boiler safety. However, as the working fluid circulation circuits cross each other, and the working fluid operational parameters change over a wide range, monitoring the Fe content and evaluating pipeline safety are very difficult. The mass transfer process of Fe in a complex water circulation system was described by constructing a network calculation model of Fe mass transfer in the steam-water circulation system of a supercritical boiler. The distribution of Fe and the corrosion/deposition rate in the system was calculated and analyzed. The influence of a Fe mass disturbance in single or multiple equipment on the mass distribution of Fe in the system is discussed. The results show that model calculation data is close to the operational data. Under the effect of cyclic mass transfer, both the granular and dissolved Fe cannot be ignored. During one cycle, about 36% of Fe was deposited on the system tube; however, the deposition amount in the steam generator and superheater section accounted for 81.2% of the total deposition amount, and the rest was deposited in the low-temperature pipeline. The influence of disturbance on other nodes in the network is quite different, which provides the possibility of discriminating the location of the disturbance node. The research results can provide a theoretical reference for water chemical control and safety during the operation.