Numerical,wind-tunnel,and atmospheric evaluation of a turbulent ground-based inlet sampling system

The use of inlets for transferring aerosols from the environment to instrumentation can introduce uncertainty in the measurement of aerosol properties. Aerosol loss during this process is a non-negligible issue that may bias the subsequent measurements. These loss mechanisms include aspiration at the inlet head and deposition/evaporation/condensation during transport through the sampling lines. Coarse-mode aerosol is significantly impacted by the aspiration and inertial loss mechanisms within an inlet system. This work uses wind tunnel experiments to investigate aerosol losses through the Storm Peak Laboratory’s (SPL) new aerosol inlet system. The inlet is used extensively for both intensive field campaigns and long-term aerosol monitoring. The results of numerical simulations of the SPL aerosol inlet sampling efficiency are provided at several wind speeds, and experimental results demonstrate the system has a 50% cut off for the coarse-mode at an aerodynamic diameter of approximately 13?μm and wind speed of 0.5?m s^?1. This investigation will lead to improved accuracy of in situ aerosol measurements at SPL and this system can be replicated at other atmospheric stations.

Copyright © 2019 American Association for Aerosol Research     

Making Large‐Area Titanium Disulfide Films at Reduced Temperature by Balancing the Kinetics of Sulfurization and Roughening

The synthesis of large‐area TiS₂ thin films is reported at temperatures as low as 500 °C using a scalable two‐step method of metal film deposition followed by sulfurization in an H₂S gas furnace. It is demonstrated that the lowest‐achievable sulfurization temperature depends strongly on the oxygen background during sulfurization. This dependence arises because Ti? O bonds present a substantial kinetic and thermodynamic barrier to TiS₂ formation. Lowering the sulfurization temperature is important to make smooth films, and to enable integration of TiS₂ and related transition metal dichalcogenides—including metastable phases and alloys—into device technology.     

Rational Design of Potent Inhibitors of a Metallohydrolase Using a Fragment-Based Approach

Metallohydrolases form a large group of enzymes that have fundamental importance in a broad range of biological functions. Among them, the purple acid phosphatases (PAPs) have gained attention due to their crucial role in the acquisition and use of phosphate by plants and also as a promising target for novel treatments of bone-related disorders and cancer. To date, no crystal structure of a mammalian PAP with drug-like molecules bound near the active site is available. Herein, we used a fragment-based design approach using structures of a mammalian PAP in complex with the Maybridge^TM fragment CC063346, the amino acid L-glutamine and the buffer molecule HEPES, as well as various solvent molecules to guide the design of highly potent and efficient mammalian PAP inhibitors. These inhibitors have improved aqueous solubility when compared to the clinically most promising PAP inhibitors available to date. Furthermore, drug-like fragments bound in newly discovered binding sites mapped out additional scaffolds for further inhibitor discovery, as well as scaffolds for the design of inhibitors with novel modes of action.     

The effect of galvanic interaction on the behaviour of the froth phase during the flotation of a complex sulphide ore

A literature review has shown that the chemical effects of grinding media on the flotation of real ores, especially those containing pyrite, are still not understood adequately. Many studies have been conducted on isolated minerals or in solutions only, and transport phenomena in the froth phase have generally been ignored in studies on galvanic interactions. A complex ore containing galena, sphalerite, chalcopyrite and significant quantities of magnetite, pyrrhotite and pyrite was used in batch flotation tests to study this problem. Metallic iron powder was added in different quantities to a ceramic ball mill in order to simulate the use of mild steel grinding media in flotation tests aimed at selectively floating chalcopyrite.An oxygen-saturated pulp milled in the presence of iron yielded the best recovery of chalcopyrite and copper-lead selectivity. Milling under a nitrogen atmosphere in the absence of metallic iron resulted in poor copper-lead selectivity. The galvanic interaction caused by the presence of iron yielded a stable, well-drained froth with low ratios of solids/water recovery and larger bubbles in the froth. However, milling in the absence of iron caused an extremely brittle froth with very fine bu bubbles, high recoveries of low grades of sulphur. In contrast with the improvement in the copper recovery and copper-lead selectivity obtained when the pulp was pre-aerated after milling in the presence of iron, no significant increase in the copper grade was observed after extensive pre-aeration when milling occurred in the absence of iron. The unsatisfactory flotation results in the absence of iron could be explained by the enhanced floatability of iron-bearing gangue minerals, which rupture films and suppress froth stability owing to bubble-overloading.     

Buckling of tube-stiffened prolate domes under external water pressure

The paper describes experimental tests carried out on three tube-stiffened prolate hemi-ellipsoidal domes under external water pressure.The tubes were stuck to the internal surfaces of these three domes, in their flanks, and the experimental tests showed that the tubes increased the buckling pressures of these domes, especially in one case, when the tube was subjected to an initial internal pressure.All three domes failed by lobar buckling, in their flanks, and showed buckling resistances much larger than similar unstiffened domes.