TiO2 ALD Coating of Amorphous TiO2 Nanotube Layers: Inhibition of the Structural and Morphological Changes Due to Water Annealing

The present work presents a strategy to stabilize amorphous anodic self-organized TiO2 nanotube layers against morphological changes and crystallization upon extensive water soaking. The growth of needle-like nanoparticles was observed on the outer and inner walls of amorphous nanotube layers after extensive water soakings, in line with the literature on water annealing. In contrary, when TiO2 nanotube layers uniformly coated by thin TiO2 using atomic layer deposition (ALD) were soaked in water, the growth rates of needle-like nanoparticles were substantially reduced. We investigated the soaking effects of ALD TiO2 coatings with different thicknesses and deposition temperatures. Sufficiently thick TiO2 coatings (≈8.4 nm) deposited at different ALD process temperatures efficiently hamper the reactions between water and F− ions, maintain the amorphous state, and preserve the original tubular morphology. This work demonstrates the possibility of having robust amorphous 1D TiO2 nanotube layers that are very stable in water. This is very practical for diverse biomedical applications that are accompanied by extensive contact with an aqueous environment

Nanocrystalline diamond protects Zr cladding surface against oxygen and hydrogen uptake : Nuclear fuel durability enhancement

In this work, we demonstrate and describe an effective method of protecting zirconium fuel cladding against oxygen and hydrogen uptake at both accident and working temperatures in water-cooled nuclear reactor environments. Zr alloy samples were coated with nanocrystalline diamond (NCD) layers of different thicknesses, grown in a microwave plasma chemical vapor deposition apparatus. In addition to showing that such an NCD layer prevents the Zr alloy from directly interacting with water, we show that carbon released from the NCD film enters the underlying Zr material and changes its properties, such that uptake of oxygen and hydrogen is significantly decreased. After 100–170 days of exposure to hot water at 360 °C, the oxidation of the NCD-coated Zr plates was typically decreased by 40%. Protective NCD layers may prolong the lifetime of nuclear cladding and consequently enhance nuclear fuel burnup. NCD may also serve as a passive element for nuclear safety. NCD-coated ZIRLO claddings have been selected as a candidate for Accident Tolerant Fuel in commercially operated reactors in 2020

Engineering Sr-doping for enabling long-term stable FAPb1xSrxI3 quantum dots with 100% photoluminescence quantum yield

The Pb substitution in quantum dots (PQDs) with lesser toxic metals has been widely searched to be environmentally friendly, and be of comparable or improved performance compared to the lead-perovskite. However, the chemical nature of the lead substitute influences the incorporation mechanism into PQDs, which has not been explored in depth. In this work, we analyzed Sr-doping-induced changes in FAPbI3 perovskites by studying the optical, structural properties and chemical environment of FAPb1−xSrxI3 PQDs. The substitution of Pb by 7 at% Sr allows us to achieve FAPb1−xSrxI3 PQDs with 100% PLQY, high stability for 8 months under a relative humidity of 40–50%, and T80 = 6.5 months, one of the highest values reported for halide PQDs under air ambient conditions. FAPb0.93Sr0.07I3 PQDs also exhibit photobrightening under UV illumination for 12 h, recovering 100% PLQY at 15 days after synthesis. The suppression of structural defects mediated by Sr-doping decreases the non-radiative recombination mechanism. By attempting to increase the Sr content in PQDs, a mixture of 2D nanoplatelets/3D nanocubes has emerged, caused by a high Pb deficiency during the FAPb1−xSrxI3 synthesis. This contribution gives a novel insight to understand how the suitable/poor Pb substitution achieved through Sr-doping dictates the photophysical properties of PQDs that may be potentially applicable in optoelectronics

Efficient and Stable Blue- and Red-Emitting Perovskite Nanocrystals through Defect Engineering: PbX2 Purification

Current efforts to reduce the density of structural defects such as surface passivation, doping, and modified synthetic protocols have allowed us to grow high-quality perovskite nanocrystals (PNCs). However, the role of the purity of the precursors involved during the PNC synthesis to hinder the emergence of defects has not been widely explored. In this work, we analyzed the use of different crystallization processes of PbX2 (X = Cl– or I–) to purify the chemicals and produce highly luminescent and stable CsPbCl3–xBrx and CsPbI3 PNCs. The use of a hydrothermal (Hyd) process to improve the quality of the as-prepared PbCl2 provides blue-emitting PNCs with efficient ligand surface passivation, a maximum photoluminescence quantum yield (PLQY) of ∼ 88%, and improved photocatalytic activity to oxidize benzyl alcohol, yielding 40%. Then, the hot recrystallization of PbI2 prior to Hyd treatment led to the formation of red-emissive PNCs with a PLQY of up to 100%, long-term stability around 4 months under ambient air, and a relative humidity of 50–60%. Thus, CsPbI3 light-emitting diodes were fabricated to provide a maximum external quantum efficiency of up to 13.6%. We claim that the improvement of the PbX2 crystallinity offers a suitable stoichiometry in the PNC structure, reducing nonradiative carrier traps and so maximizing the radiative recombination dynamics. This contribution gives an insight into how the manipulation of the PbX2 precursor is a profitable and potential alternative to synthesize PNCs with improved photophysical features by making use of defect engineering

Multi-Factor Optimization and Factor Interactions during Product Innovation

In this paper, we develop core of an expert system for planning of innovation. The practical outcome of the paper is based on rules determination for search of perspective innovation and its distinguish from commercially unperceptive innovation. The second practical outcome of the paper is a research of interactions between factors during optimization of the product. In general, we gain process synergy, which can be a source of competitive advantage during product innovation in the presence of organizational complexity by systematically moving through the process definition, control, and improvement elements. The improvement elements can cause interactions between these elements (or factors/process parameters). First, we have to distinguish between synergistic and antagonistic interactions. For synergistic interaction can be used graphic illustration - lines on the plot do not cross each other. In contrast, for antagonistic interaction, the lines on the plot cross each other. In this case, the change in mean response for factor at low level is noticeable high compared to high level. Searching for positive interactions leading to the creation of synergies in the performances we can do at each stage of management innovations. At first, we realize only part of the possible gain, with unrealized potential remaining. Using process control, over time, we stabilize our process and obtain additional limited gain. Using process improvement, we can realize additional gain (it looks as short vertical line during the time), with some potential gain remaining. When new, feasible options develop, we can redefined our process and continue with our control and improvement efforts. Hence, each process-related issue definition, control, improvement has a distinct role to play. Confusion between roles or the omission of any of the roles creates disharmony and frustration in the production system, which ultimately limits production system effectiveness and efficiency. Sometimes, in the presence of confusion, it is possible that effectiveness and efficiency may decrease. In this situation, we hope to learn from our negative factor interactions (or failures) and subsequently improvement trends in long term with using sophisticated methods and own intuition. This paper objective is to create rules for planning innovation expert system. According to this rules will be possible to distinguish perspective innovation from commercially unperceptive innovation. The second paper objective is to explore interactions between factors during a product optimization. For this purpose will be used the methodology based on minimization of logic functions and design of experiments (analytical tools of DOE)

Reducing production variability using factorial optimisation: A case study from the food-packaging industry

In industry, many phenomena and events that arise that cannot be predicted because they represent changes in production. Such random effects and events can significantly influence all aspects of the manufacturing process. The optimal design of any production system can be generated based on a complete, correct set of input information. However, such a requirement is unrealistic, as manufacturing systems are affected by several random factors. Current practice is based on determining the worst possible conditions in which a production system could run (the longest possible duration of outages in the supply chain, extreme weather conditions in agriculture, etc.). This article aimed to identify factors influencing the variability of the manufacturing process in the field of CNC (Computer Numerical Control) machining for food production. A secondary aim was to minimise the variability of the manufacturing process using a factorial design. The variability reduction was verified using statistical F-tests. The study on reducing variability in production was performed at the Czech Yuncheng Plate Making Co., Ltd., a professional rotogravure cylinder–making company. The cylinders are used for the food industry