Hydrothermal Synthesis of Pollucite (CsAlSi2O6) Powders

Pollucite (CsAlSi₂O₆) powders were produced by hydrothermal synthesis from relatively inexpensive precursors. The pollucite powders were comprised of polycrystalline particles with dimensions of hundreds of nanometers consisting of 25-75 nm crystallites. The polycrystalline particles were near stoichiometric composition. The pollucite powders were mixed with a poly(ethylene glycol) binder, pressed into disks, and sintered at temperatures from 1450° to 1550°C for 10 h. The resulting sintered ceramics had densities >80% of theoretical density and, in the best case, >97% of theoretical density.     

Effect of composition gradient in Cu(In,Al)Se2 solar cells

Cu(In,Al)Se₂ (CIAS) thin films were prepared by a three-stage evaporation process. In this experiment, the composition ratio of Cu/(In+Al) at the end of the second stage (Cu/III_2nd) was changed from 1.1 to 1.7. The CIAS films showed an Al distribution with a V-shape profile. The valley depth of the V-shape from the surface increased with increasing the Cu/III_2nd ratio. The valleys of the V-shape for the films with the Cu/III_2nd ratio of 1.1–1.7 were located at approximately 0.3–1.0 μm from the film surface, respectively. The rms surface roughness increased from 40 nm for Cu/III_2nd=1.1 to 90 nm at Cu/III_2nd=1.3 and then saturated for greater Cu/III_2nd ratios. Solar cells with the Al/ITO/ZnO/CdS/CIAS/Mo/soda-lime glass structure were fabricated. The fill factor was seen to decrease while the product of short-circuit current and open-circuit voltage remained constant. The reverse saturation current increased when the Cu/III_2nd ratio is greater than 1.3 which is a behavior of the surface roughness. Cu/III_2nd ratios greater than 1.3 lead to the distant position of V-shape from the surface and the increase in surface roughness.     

Double-Averaging Concept for Rough-Bed Open-Channel and Overland Flows: Theoretical Background

The goal of this paper is to discuss the spatial averaging concept in environmental hydraulics and develop it further by considering transport equations for fluid momentum, passive substances, and suspended sediments. The averaging theorems, the double-averaged (in time and in space) fluid momentum equation, and advection-diffusion equations for a passive substance and suspended sediments are introduced and their limitations and applications for modeling rough-bed flows, experimental design, and data interpretation are discussed. The suggested equations differ from those considered in terrestrial canopy aerodynamics and porous media hydrodynamics by accounting for roughness mobility, change in roughness density in space and time, and particle settling effects for the case of suspended sediments. We show that the form of the double-averaged equations may depend on the type of decomposition of flow variables and that this difference may have important implications for modeling. We also show that the suggested methodology offers better definitions for hydraulic characteristics, variables, and parameters such as flow uniformity, flow two dimensionality, and bed shear stress.     

Operating conditions of batteries in off-grid renewable energy systems

Operating conditions in off-grid renewable energy systems (RES) vary significantly in different applications and locations. To describe RES and the operating conditions of their components it is useful to define categories of similar operating conditions. Categories can also be used for lifetime considerations of RES components, for making recommendations and for analysing the properties and performance of a RES and its components. Categories support system designers and an economic analysis. This paper describes the process and the results of creating RES categories of similar operating conditions for batteries. Categories are defined in such a way that batteries belonging to the same category are subjected to similar operating conditions and a similar combination of stress factors. The results provide a comprehensive overview of battery operating conditions in existing off-grid renewable energy systems. This work is part of the EU research project Benchmarking.¹     

Reinforcement Learning for Structural Control

This study focuses on improving structural control through reinforcement learning. For the purposes of this study, structural control involves controlling the shape of an active tensegrity structure. Although the learning methodology employs case-based reasoning, which is often classified as supervised learning, it has evolved into reinforcement learning, since it learns from errors. Simple retrieval and adaptation functions are proposed. The retrieval function compares the response of the structure subjected to the current loading event and the attributes of cases. When the response of the structure and the case attributes are similar, this case is retrieved and adapted to the current control task. The adaptation function takes into account the control quality that has been achieved by the retrieved command in order to improve subsequent commands. The algorithm provides two types of learning: reduction of control command computation time and increase of control command quality over retrieved cases. Results from experimental testing on a full-scale active tensegrity structure are presented to validate performance.     

Prandtl/Schmidt number effect on temperature distribution in a generic combustor

As a benchmarking of turbulence scalar transfer modeling, the effect of Prandtl/Schmidt number on the temperature field of a diffusion flame model combustor has been investigated. Some of the numerical results, obtained from the eddy dissipation combustion model with the turbulent Prandtl/Schmidt number varying from 0.25 to 0.85, are presented and compared with a comprehensive experimental database. It is found that the turbulent Prandtl/Schmidt number has significant effect on the predicted temperature field in the combustion chamber. This is also true for the temperature profile along the combustor wall. In contrast, its effect on the velocity field is insignificant in the range considered. With the optimized turbulent Prandtl/Schmidt number, both velocity and temperature fields can be reasonably and quantitatively predicted. For the present configuration and operating conditions, the optimal Prandtl/Schmidt number is 0.5, and lower than the typical used value of ～0.7. This study suggests that the current method for scalar transfer modeling in turbulent reacting flows should be improved and new approaches should be developed.     

THE POLITICS OF CYBER

We live in a world of competing nation states, proxies of those states and non-nation state actors. This competition manifests itself in any number of ways – conflict, sanctions, restrictions, embargo, assassinations, etc. Clausewitz’s suggested “War as politics by other means” so, the natural conclusion is cyber espionage, cyber-attacks and cyber influence operations, are merely manifestations of a policy clash between two or more competing powers or proxies. This article suggests the development of nation state Advanced Persistent Threat (APT) capability is a direct result of the collision of competing national interests and the national policy which drives those interests. Surprising no one the work required to counter these cyber threats is technically difficult and legally problematic. Charting a course from the early days of website defacement to Distributed Denial of Service Attacks (DDOS) the evolution of capability of APT actors has been significant and rapid. Contrasting this rapid advancement of Chinese, Iranian, Russian and North Korean APT actors is the lack of an effective dissuasive policy and a decidedly placid global political and legal response. With the notable American judicial system and policy apparatus it seems evident the USA remains a global cyber police force using a potent and extraordinary Extraterritorial jurisdiction (EJT) authority far outside of American borders to target both criminal and nation state actors.     

Untargeted metabolomics of human plasma reveal lipid markers unique to chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis

Chronic obstructive pulmonary disease (COPD) is characterised by airway inflammation and progressive airflow limitation, whereas idiopathic pulmonary fibrosis (IPF) is characterised by a restrictive pattern due to fibrosis and impaired gas exchange. We undertook metabolomic analysis of blood samples in IPF, COPD and healthy controls (HC) to determine differences in circulating molecules and identify novel pathogenic pathways. An untargeted metabolomics using an ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometer (UHPLC-QTOF-MS) was performed to profile plasma of patients with COPD (n = 21), and IPF (n = 24) in comparison to plasma from healthy controls (HC; n = 20). The most significant features were identified using multiple database matching. One-way ANOVA and variable importance in projection (VIP) scores were also used to highlight metabolites that influence the specific disease groups. Non-polar metabolites such as fatty acids (FA) and membrane lipids were well resolved and a total of 4805 features were identified. The most prominent metabolite composition differences in lipid mediators identified at ∼2–3 fold higher in both diseases compared to HC were palmitoleic acid, oleic acid and linoleic acid; and dihydrotestosterone was lower in both diseases. We demonstrated that COPD and IPF were characterised by systemic changes in lipid constituents such as essential FA sampled from circulating plasma.