Saturated Environment Research Articles

Adaptive Resilient Control for Interconnected Vehicular Platoon With Fault and Saturation

This paper investigates the problem of the interconnected heterogeneous vehicular platoon in the presence of actuator fault of a vehicle, actuator saturation, and complex environment disturbances such as road slope, wind gust, and so on. First of all, a quadratic spacing error policy is applied to improve the vehicle platoon stability despite any vehicle suffering from actuator fault. Then, adaptive estimation laws are introduced to tackle the complex environment disturbances and the unknown upper bound of the actuator saturation approximation function. A robust adaptive sliding mode resilient control law is proposed to achieve the resilient ability and ensure the platoon system recover to the stable states in finite-time even if the occurrence of actuator fault. Finally, the string stability in finite-time of the platoon system is proved, the interconnected heterogeneous vehicular platoon system with seven vehicles is utilized to demonstrate the validity of the proposed control scheme.

The Effects of Surface Curvature and Temperature on Charge Transfer During Ice‐Ice Collisions

Repetitive collisions of sublimating ice surfaces, created by freezing liquid water, produced charge separation Q of a magnitude (pC) comparable to earlier results of vapour-grown ice crystals repetitively collided in a saturated environment. Those results had been explained by a theory of charge distribution in a quasi-liquid surface layer QLL mediated at the moment of impact by collisional melting. The present results are from long duration contacts (15ms) with transfer of kinetic energy estimated to be a factor of 104 greater, and charging-rate 98% slower. They do not support an assumption in that proposed mechanism of collisional melting, and are contrary to the basic assumptions of that theory: that significant Q occurs only in growing surfaces (that is, in a supersaturated condition which implies the presence of liquid water), that were originally grown from vapour, and for which contact is less than 1ms. The results are opposite to a rule that in the case of differing surfaces (vapour-grown, and rimed) that which is greater sublimating charges negatively. Here, for surfaces of frozen water, the surface further from equilibrium becomes positively charged. The results are not inconsistent with recent reports of simulations that suggest that the thickness of a quasi-liquid layer QLL in sublimating surfaces may not be less than the equilibrium value. Apparently, for differing ice surfaces, Q is of the order of 1fC whereas for collisions of similar ices on metal substrates (whether both vapour-deposited, or both frozen liquid water) Q is of the order of 1pC.

Size-Dependent Dried Colloidal Deposit and Particle Sorting via Saturated Alcohol Vapor-Mediated Sessile Droplet Spreading

We experimentally and theoretically investigate a distinct problem of spreading, evaporation, and the associated dried deposits of a colloidal particle-laden aqueous sessile droplet on a surface in a saturated alcohol vapor environment. In particular, the effect of particle size on monodispersed suspensions and efficient self-sorting of bidispersed particles have been investigated. The alcohol vapor diffuses toward the droplet's curved liquid-vapor interface from the far field. The incoming vapor mass flux profile assumes a nonuniform pattern across the interface. The alcohol vapor molecules are adsorbed at the liquid-vapor interface, which eventually leads to absorption into the droplet's liquid phase due to the miscibility. This phenomenon triggers a liquid-vapor interfacial tension gradient and causes a reduction in the global surface tension of the droplet. This results in a solutal Marangoni flow recirculation and spontaneous droplet spreading. The interplay between these phenomena gives rise to a complex internal fluid flow within the droplet, resulting in a significantly modified and strongly particle-size-dependent dried colloidal deposit. While the smaller particles form a multiple ring pattern, larger particles form a single ring, and additional "patchwise" deposits emerge. High-speed visualization of the internal liquid-flow revealed that initially, a ring forms at the first location of the contact line. Concurrently, the Marangoni flow recirculation drives a collection of particles at the liquid-vapor interface to form clusters. Thereafter, as the droplet spreads, the smaller particles in the cluster exhibit a "jetlike" outward flow, forming multiple ring patterns. In contrast, the larger particles tend to coalesce together in the cluster, forming the "patchwise" deposits. The widely different response of the different-sized particles to the internal fluid flow enables an efficient sorting of the smaller particles at the contact line from bidispersed suspensions. We corroborate the measurements with theoretical and numerical models wherever possible.

Evaluating the impact of aggregation and RTS/CTS schemes on IEEE 802.11 based Linear Wireless Ad‐Hoc Networks

AbstractThe Linear Wireless Ad‐Hoc Network (Linear WANET), as a branch of the Ad‐Hoc network, refers to a self‐organizing multi‐hop wireless network in which nodes are arranged linearly. Frame aggregation and RTS/CTS schemes are introduced in IEEE 802.11 aims to improve network transmission performance. However, the traditional mechanisms may not have good adaptability in linear multi‐hop networks. Thus, we defined a Linear WANET simulation model based on the IEEE 802.11 protocol. We established this model on the NS‐3 network simulator to perform A‐MSDU, A‐MPDU, and two‐level frame aggregation simulation and analyzed the aggregation performance under different channel environments. Meanwhile, the RTS/CTS and TXOP mechanisms were also simulated in this article. We analyzed the performance of each mechanism in a Linear WANET under saturated and unsaturated environments. We found that the linear multi‐hop characteristic has a significant impact on the performance of the frame aggregation mechanism. In the Linear WANET, the A‐MSDU mechanism can improve system performance to a limited extent, but at the same time, it will increase the packet loss rate and delay. So, the two‐level aggregation can improve the maximum throughput of the system with better channel conditions. In the case of single A‐MPDU aggregation, there has a lowest data delivery interval that the Linear WANET system can withstand. The A‐MPDU mechanism is a better choice for the poor channel conditions with unsaturated system throughput. Meanwhile, we also found that the native TXOP mechanism cannot effectively improve the system efficiency of Linear WANET. The RTS/CTS mechanism can enhance system throughput performance in most cases, especially in a saturated throughput environment.

Biomineralisation to Increase Earth Infrastructure Resilience.

The vulnerability of buildings and structures to rain and flooding due to a lack of adaptive capacity is an issue all over the world. Exploring the bio-resources availability and engineering performance is crucial to increase infrastructure’s resilience. The current study analyses earth-based mortars using mineral precipitation as a biostabiliser (bio) and compares their performance with cement-based mortars. Cultures of S. oneidensis with a concentration of 2.3 × 108 cfu/mL were used to prepare earth-based and cement-based mortars with a ratio of 6% of binder. Microstructure analyses through SEM/EDS, water absorption, moisture buffering, mechanical strength, and porosity are discussed. The biostabiliser decreases water absorption in tidal-splash and saturated environments for earth and cement mortars due to calcium carbonate precipitation. The biostabiliser can prevent water migration more effectively for the cement-based (60% reduction) than for the earth-based mortars (up to 10% reduction) in the first 1 h of contact with water. In an adsorption/desorption environment, the conditions favour desorption in cem+bio, and it seems that the biostabiliser precipitation facilitates the release of the chemicals into the mobile phase. The precipitation in the earth+bio mortar porous media conditions favours the adsorption of water molecules, making the molecule adhere to the stationary phase and be separated from the other sample chemicals. The SEM/EDS performed for the mortars confirms the calcium carbonate precipitation and shows that there is a decrease in the quantity of Si and K if the biostabiliser is used in cement and earth-mortars. This decrease, associated with the ability of S. oneidensis to leach silica, is more impressive for earth+bio, which might be associated with a dissolution of silicate structures due to the presence of more water. For the tested earth-based mortars, there was an increase of 10% for compressive and flexural strength if the biostabiliser was added. For the cement-based mortars, the strength increase was almost double that of the plain one due to the clay surface negative charge in the earth-based compositions.

Durability of GFRP connectors under sustained compression load for use in sandwich walls

Precast concrete sandwich panels are used to fulfil the rising thermal requirements. The sandwich walls consist of three layers, a facing, a thermal insulation layer, and a load bearing layer. The two outer layers are coupled by connectors made of glass-fibre reinforced polymer. A lack of knowledge about load-bearing behaviour prevents the removal of sustained compressive loads. In the context of this article, tests under sustained compressive load are presented. To represent closely the in service-conditions of sandwich walls, the examined connectors were subjected to a saturated alkaline concrete environment as well as to a specified stress level till failure occurs. Thus, the experimental setup combines alkaline resistance and creep rupture tests into one comprehensive testing. By using temperature effects as an accelerating factor, reasonable test durations were enabled. The obtained time to failure line was determined to extrapolate the characteristic values of the long-term strength for a service life up to 50 years. The test results are compared and evaluated with existing test results under a sustained tensile load.

Evaluation of the Pitting Corrosion of Modified Martensitic Stainless Steel in CO2 Environment Using Point Defect Model

Pitting corrosion is a significant concern for the broader application of stainless steel in modern industries in which metal and metal alloy are detached preferentially from susceptible parts on the surface, resulting in the creation of holes in passivated alloys that are exposed to an aqueous, neutral electrolyte containing corrosive species. Exposure of SS to brines leads to the localized loss of surface passivity and the onset of isolated pitting, which render the equipment or piping unfit for service. In the present study, the passive layer behavior and the pitting corrosion of the modified martensitic stainless steel (MMSS) were evaluated in a saturated CO2 environment (pH~5) with different NaCl concentrations and temperatures, using various electrochemical techniques. It was found that by increasing the temperature up to 60 °C, the corrosion resistance of the MMSS increased; however, the corrosion rate dramatically increased at 80 °C, indicating the destruction of the oxide layer. According to the point defect model (PDM) results, the calculated values of polarizability (α), metal cation diffusivity (D), and the rate of annihilation of cation vacancies (jm), reveal a strong dependence on the solution temperature.

Effect of calcium on X65 carbon steel pitting in saturated CO2 environment

Micro-pits could propagate during in-service life in facilities such as crude oil storage tanks in which calcium salts are present. Calcium is known to influence pit initiation and propagation but explanation on pitting kinetics on low carbon steel remains debatable. More so, knowledge is lacking on how different CaCO3 polymorphs influence pitting in low carbon steel. The effect of calcium on pitting in UNS K03014 (X65) carbon steel was investigated using potentiostatic induced pits in an environment typical of crude oil storage tanks and liquid aquifers. SEM, EDX and XRD investigations were performed to profile formed corrosion products followed by surface profilometry to determine the extent of pit growth. It was revealed that Ca2+influence general and pitting corrosion while the kinetics of pit propagation depends on the nature of the calcium carbonate polymorph that forms on steel surface. Pit propagation was high when amorphous CaCO3 deposit formed at pH 3.8 but pit growth retarded as aragonite started to grow on the steel surface.

Application of VR Intelligent Technology in Fire Evacuation Simulation of Urban Rail Transit Station

With the expansion of the city and the rapid development of public transport, the subway as a mass public transport means to bear a very large number of passengers, so that in the morning and evening rush hour, some subway stations are almost saturated. Once a disaster happens in a subway station, the saturated space environment makes it difficult for passengers to evacuate. In addition, the subway station is usually located underground, buried depth of about 10m-30m, the accident station passengers have to overcome their own gravity to the ground to escape, which increases the difficulty of passenger evacuation.Fire is one of the biggest security hidden dangers in subway operation. Once it happens, it will bring huge loss to the safety of social resources and people's life and property. On the basis of summarizing the present situation of fire evacuation in urban rail transit stations at home and abroad, this paper firstly analyzes and studies the factors that affect the fire evacuation ability of stations. Then through the station fire evaluation index to build the safety evacuation evaluation index system. Finally, through the VR technology, computer simulation, field investigation and other methods to quantify the index, the Fuzzy Network analysis of the station fire safety evacuation capacity comprehensive evaluation and put forward targeted countermeasures and suggestions.

Characterisation of Single-Phase Fluid-Flow Heterogeneity Due to Localised Deformation in a Porous Rock Using Rapid Neutron Tomography.

The behaviour of subsurface-reservoir porous rocks is a central topic in the resource engineering industry and has relevant applications in hydrocarbon, water production, and CO sequestration. One of the key open issues is the effect of deformation on the hydraulic properties of the host rock and, specifically, in saturated environments. This paper presents a novel full-field data set describing the hydro-mechanical properties of porous geomaterials through in situ neutron and X-ray tomography. The use of high-performance neutron imaging facilities such as CONRAD-2 (Helmholtz-Zentrum Berlin) allows the tracking of the fluid front in saturated samples, making use of the differential neutron contrast between “normal” water and heavy water. To quantify the local hydro-mechanical coupling, we applied a number of existing image analysis algorithms and developed an array of bespoke methods to track the water front and calculate the 3D speed maps. The experimental campaign performed revealed that the pressure-driven flow speed decreases, in saturated samples, in the presence of pre-existing low porosity heterogeneities and compactant shear-bands. Furthermore, the observed complex mechanical behaviour of the samples and the associated fluid flow highlight the necessity for 3D imaging and analysis.

Point-of-Sale Health Communication Campaigns for Cigarillos and Waterpipe Tobacco: Effects and Lessons Learned from Two Cluster Randomized Trials

ABSTRACT Many adolescents and young adults hold erroneous beliefs that cigarillos and waterpipe tobacco (WT) are safer than cigarettes, contributing to use. Communication campaigns can correct misperceptions and increase risk beliefs. We tested point-of-sale (POS) communication campaigns focused on chemical exposure for cigarillos and WT. We conducted two cluster randomized trials at 20 gas stations with convenience stores (10 stores for cigarillos, 10 for WT) in North Carolina between June and November 2017. Within each trial, stores were randomly assigned to either the intervention (campaign messages displayed) or a no message control condition. We conducted intercept surveys with repeated cross-sectional samples of 50 adolescents and young adults (ages 16–25) per store, at baseline and follow-up. There were 978 participants (mean age = 20.9 years) in the cigarillo trial, and 998 participants (mean age = 21.0 years) in the WT trial. Rates of campaign exposure were low (26% for cigarillos; 24.3% for WT). The cigarillo campaign increased knowledge that ammonia is in cigarillo smoke (p < .01). There were also significant increases in knowledge about ammonia and cyanide in cigarillo smoke and arsenic in WT smoke (p < .05) in the sub-sample who reported exposure to the campaign. No differences were found in outcome expectancies, product attitudes, worry about chemical exposure, or behavioral intentions in either campaign. Garnering attention for communication campaigns in saturated POS environments, often dominated by tobacco advertising, is challenging. Our study demonstrates the feasibility of anti-tobacco campaigns at the POS and points to several lessons learned for future POS campaigns.

Coordination mechanism of aluminum with oxalate and fluoride in aluminum crystallization from vanadium extraction wastewater

Aluminum speciation is complex in a solution where organic and inorganic ligands coexist, and aluminum can form different complexes with various ligands. In this paper, the coordination mechanism of aluminum with oxalate and fluoride in aluminum recovery from vanadium extraction wastewater was investigated. By comparing the process of recovering aluminum with oxalate and fluoride precipitation, oxalate crystallization is found to perform better with vanadium extraction wastewater. Under optimum conditions, the crystallization percentage of aluminum was 87.10%. K3Al(C2O4)3·3H2O was obtained and characterized by XRD and FTIR, and the total recovery of aluminum was 80%. The coordination mechanism and migratory behavior of aluminum with oxalate and fluoride during crystallization were studied by thermodynamic simulation and quantum chemical calculation. Results showed that aluminum primarily exists as AlF2+, AlF2+, AlC2O4+, and Al(C2O4)2 in vanadium extraction wastewater. With the addition of K2C2O4 and an increase in solution pH, these complexes were coordinated by C2O42− and formed Al(C2O4)33– complex anions, which provided a saturated solution environment for K3Al(C2O4)3·3H2O crystallization. The DFT simulation showed that the Gibbs free energies of the coordination reactions for Al(C2O4)33– were negative, which indicates that these coordination reactions can proceed spontaneously. This study is important when enriching the coordination mechanism of aluminum and improving the comprehensive utilization rate of resources for vanadium-bearing shale.

Monitoring method for leakage current of transmission line insulators under typical environmental conditions

There are many factors affecting insulator leakage current of transmission line, resulting in low accuracy of leakage current monitoring. This paper designs a monitoring method for insulator leakage current of transmission line under typical environmental conditions. The influence of different factors on the accuracy of leakage current monitoring is analyzed. Based on the fuzzy mathematics theory, the insulator operating characteristic quantity is analyzed, and the uncertain factors in the insulator operating characteristic quantity are calculated, so as to realize the insulator leakage current monitoring of transmission line under typical environmental conditions. The example analysis shows that the leakage current monitoring accuracy of the method studied in this paper is high in the case of no arc, local arc, adjacent flashover, pollution and saturated environment, which proves the effectiveness of the method studied.

On the wetting behavior of surfaces in boiling

Nucleate boiling heat transfer is strongly influenced by surface wettability as characterized by the Young's contact angle, θY. The contact angle is usually obtained from measurements on sessile droplets on horizontal test surfaces, but in the case of water at high temperatures and pressures, θY values from droplet experiments appear to be typically 30°–50° higher than values needed to explain bubble departure sizes for similar surfaces and temperatures. We explain the differences between θY values for droplets and vapor bubbles by using the surface adsorption theory of Adamson. This theory suggests that in the case of bubble formation in high pressure boiling, as the non-wetted surface inside the bubble is in contact with a saturated vapor, it will be covered by an adsorbed liquid layer of nanoscale thickness. Droplet experiments, on the other hand, generally use autoclaves pressurized by permanent gases in which the vapor pressure is far below saturation: in these relatively dry gases, the adsorbed liquid nanolayer is expected to be absent. We suggest that the presence of the adsorbed layer in the case of vapor bubbles will increase the work of formation of a new wetted surface by an amount comparable to the liquid surface tension, resulting in a significant reduction in θY. We show that by applying Adamson's model with plausible choices for unknown parameters, it is possible to explain the magnitude of the differences in θY in bubble and droplet experiments and to explain why θY appears much less sensitive to surface material conditions in the case of departing vapor bubbles than in the case of sessile droplets. We conclude that θY measurements for sessile droplets on heated surfaces in pressurized gas rather than saturated vapor environments may not be relevant to vapor bubbles and values should not be used directly in models of nucleate boiling.

Enabling Quasi‐2D Perovskite‐Compatible Growth Environment for Efficient Light‐Emitting Diodes

AbstractDespite the rapid advancement in electroluminescence efficiencies of perovskite light‐emitting diodes (PeLEDs), it remains challenging to achieve efficient and reproducible devices. Herein, an effective vapor‐assisted growth (VAG) method is proposed to develop quasi‐2D perovskite thin‐films via creating a saturated dimethyl sulfoxide vapor environment. The VAG‐optimized perovskite films with a composition of PEA2(FAPbBr3)n−1PbBr4 display uniformly distributed nanograins with graded energy landscape and compact surface, contributing to enhanced radiative and suppressed nonradiative recombination. Consequently, the PeLEDs incorporating VAG‐based films with a device architecture of indium tin oxide/poly(9,9‐dioctylfluorene‐alt‐N‐(4‐sec‐butylphenyl)‐diphenylamine)/perovskite/(1,3,5‐tris(phenyl‐2‐benzimidazolyl)benzene)/Yb/Ag demonstrate a peak current efficiency of 27.1 cd A−1 (@ 532 nm) with an external quantum efficiency of 6.50% and a maximum luminance of 17 610 cd m−2. Notably, champion PeLEDs manifest considerably curtailed efficiency roll‐off as ≈50% of the peak efficiency is preserved even at a very high luminance of 15 000 cd m−2. Meanwhile, VAG‐based PeLEDs exhibit improved reproducibility compared to the control counterparts. It is anticipated that this work would promote the development of reliable solution‐processing methods toward stabilized perovskite‐based photonics.

Soybean base saturation stress: Selecting populations for multiple traits using multivariate statistics

AbstractOne of the main objectives of soybean breeding programs is the search for genotypes that are both high yielding and tolerant to abiotic stresses. Brazilian Cerrado, the main grain‐producing region in the country, is characterised by naturally acidic and low fertility soils that consequently have low base saturation. Therefore, identifying genotypes with good performance for favourable and low base saturation stress conditions is of fundamental importance for crop improvement. The objective of this study was to select F3 soybean populations for multiple traits under contrasting base saturation conditions. Field experiments were carried out in two crop seasons in randomised block design with three replicates and 10 F3 populations (P1, P2, P3, P4, P5, P6, P7, P8, P9 and P10). In the first experiment, F3 populations were evaluated without base saturation correction (V = 30%, low saturation), while in the second experiment, limestone was applied 3 months before the start to raise the base saturation to 60% (recommended saturation). We evaluated physiological, nutritional, agronomic and spectral variables. Multivariate analysis was performed to know the populations’ performance and the interrelationship between variables and populations in the saturation conditions evaluated. The F3 populations showed differential performance for all traits across the conditions tested, enabling the identification of the best populations for each specific condition and both base saturation environments. Population P2 stood out under both low and recommended base saturation conditions and can be used in F4 plant selection to obtain superior lines for physiological and agronomic traits and vegetation indices.

Spaceborne differential absorption radar water vapor retrieval capabilities in tropical and subtropical boundary layer cloud regimes

Abstract. Differential absorption radar (DAR) near the 183 GHz water vapor absorption line is an emerging measurement technique for humidity profiling inside of clouds and precipitation with high vertical resolution, as well as for measuring integrated water vapor (IWV) in clear-air regions. For radar transmit frequencies on the water line flank away from the highly attenuating line center, the DAR system becomes most sensitive to water vapor in the planetary boundary layer (PBL), which is a region of the atmosphere that is poorly resolved in the vertical by existing spaceborne humidity and temperature profiling instruments. In this work, we present a high-fidelity, end-to-end simulation framework for notional spaceborne DAR instruments that feature realistically achievable radar performance metrics and apply this simulator to assess DAR's PBL humidity observation capabilities. Both the assumed instrument parameters and radar retrieval algorithm leverage recent technology and algorithm development for an existing airborne DAR instrument. To showcase the capabilities of DAR for humidity observations in a variety of relevant PBL settings, we implement the instrument simulator in the context of large eddy simulations (LESs) of five different cloud regimes throughout the trade-wind subtropical-to-tropical cloud transition. Three distinct DAR humidity observations are investigated: IWV between the top of the atmosphere and the first detected cloud bin or Earth's surface; in-cloud water vapor profiles with 200 meter vertical resolution; and IWV between the last detected cloud bin and the Earth's surface, which can provide a precise measurement of the sub-cloud humidity. We provide a thorough assessment of the systematic and random errors for all three measurement products for each LES case and analyze the humidity precision scaling with along-track measurement integration. While retrieval performance depends greatly on the specific cloud regime, we find generally that for a radar with cross-track scanning capability, in-cloud profiles with 200 m vertical resolution and 10 %–20 % uncertainty can be retrieved for horizontal integration distances of 100–200 km. Furthermore, column IWV can be retrieved with 10 % uncertainty for 10–20 km of horizontal integration. Finally, we provide some example science applications of the simulated DAR observations, including estimating near-surface relative humidity using the cloud-to-surface column IWV and inferring in-cloud temperature profiles from the DAR water vapor profiles by assuming a fully saturated environment.

Comparative Studies on Hydraulic Fracturing Fluids for High-Temperature and High-Salt Oil Reservoirs: Synthetic Polymer versus Guar Gum.

The increasing energy demand has prompted engineers to explore deeper wells where rich oil and gas reserves exist. However, the high-temperature and high-salt conditions have impeded the further application of traditional water-based fracturing fluids in such reservoirs. Therefore, it is urgent to develop fracturing fluids that are suitable for such geographic characteristics. In this study, for the first time, a novel synthetic polymer, poly-(acrylamide-co-acrylic acid-co-2-acrylamido-2-methyl-1-propanesulfonic acid) (P3A), was investigated as a rheological modifier for water-based fracturing fluids in high-temperature and high-salt conditions and compared with a guar gum system. Results showed that the apparent viscosity increased with increasing P3A and guar gum concentrations, and the thickening ability of P3A was much better than that of guar gum. Despite the better shear and temperature resistance and proppant suspension ability of guar gum fluids in high-temperature and saturated salt conditions, plentiful solid residues after gel-breaking have prevented their progress in the petroleum industry. P3A fluids have no residues, but the unsatisfying proppant suspension capability and high dosage encourage us to promote their rheological performance via interaction with an organic zirconium crosslinker. Infrared spectroscopy and scanning electron microscopy were applied to guarantee the successful reaction of P3A with the crosslinker. The subsequent investigation indicated that the transformed fracturing fluid exhibited remarkably improved thickening capability and satisfying rheological performance in terms of temperature and shear resistance and proppant-carrying ability as well as gel-breaking results in a high-temperature and saturated salt environment. All of the above results suggest the potential application of crosslinked P3A in hydraulic fracturing for the reservoirs with hostile conditions, and this article also provides a new orientation for synthetic polymers utilized in the oil and gas industry.

Dramatic Maturing Effects on All Inorganic CsPbBr3 Perovskite Solar Cells under Different Storage Conditions

As perovskite solar cells have yielded impressive efficiency at a low cost, the focus has shifted to increase their service life as they are plagued by rapid degradation. Refreshingly, CsPbBr3 solar cells built on a conductive ZnO nanowire electron transport layer with a graphite counter electrode not only avoided degradation but also showed some of the reverse trends under specific conditions, showing significant maturation over time. In this work, this phenomenon is first confirmed to be reproducible from a large sample size with on average a 40 ± 10% increase in efficiency after 2 weeks of storage. To explore the mechanisms of this positive maturing effect, samples were stored under different controlled conditions and tested regularly by using scanning electron microscopy, powder X-ray diffraction, current–voltage (IV) curves, and impedance spectroscopy. The samples stored in a methanol atmosphere presented a dramatic positive effect, giving a 4-fold increase in efficiency after 2 days of storage. However, in the saturated H2O environment, the device performance rapidly degraded. By observing the solar cell performance affected by various storage conditions, including various solvent vapors, light illumination, and an inert gas (N2), we suggest three possible complementary factors. First, solvents shifted the equilibrium of crystal phase ratio of CsPbBr3 to CsPb2Br5. Second, the CsPbBr3 grain size was reduced with improved electrical contact with the conductive ZnO nanowires. Finally, ion migration and accumulation lead to the formation of local p–n junctions at crystal grain boundaries with improved charge separation. This was evidenced by the increased kinetic relaxation times on ionic time scales. Rather than degrading, under appropriate conditions, these cells were able to increase in value/efficiency over storage time. By elucidating the underlying mechanisms for the CsPbBr3 solar cell stability, the work offers guidelines for improving perovskite solar cell long-term efficiency.

Deep Fusion of a Skewed Redundant Magnetic and Inertial Sensor for Heading State Estimation in a Saturated Indoor Environment

Robust attitude and heading estimation in an indoor environment with respect to a known reference are essential components for various robotic applications. Affordable Attitude and Heading Reference Systems (AHRS) are typically using low-cost solid-state MEMS-based sensors. The precision of heading estimation on such a system is typically degraded due to the encountered drift from the gyro measurements and distortions of the Earth’s magnetic field sensing. This paper presents a novel approach for robust indoor heading estimation based on skewed redundant inertial and magnetic sensors. Recurrent Neural Network-based (RNN) fusion is used to perform robust heading estimation with the ability to compensate for the external magnetic field anomalies. We use our previously described correlation-based filter model for preprocessing the data and for empowering perturbation mitigation. Our experimental results show that the proposed scheme is able to successfully mitigate the anomalies in the saturated indoor environment and achieve a Root-Mean-Square Error of less than [Formula: see text] for long-term use.