Impedance spectroscopy study of SrTiO3 pulse laser deposited photoelectrodes

Strontium titanate (STO) is an oxide that has found application in several technological areas and is a candidate electrode for photoelectrochemical cells (PECs). In this study, STO thin films were prepared via pulsed laser deposition to function as PEC electrodes. Effects of post-deposition annealing in a reducing environment on the photocatalytic activity of these electrodes are characterized by measurements of optical and electrochemical properties of the films. These observations are used to obtain insight into how the crystal and electronic properties of these electrodes are affected by the annealing process. Low annealing temperatures produce non-crystalline STO films that exhibit low photocatalytic activity. Annealing at 500 °C and higher allowed the formation of crystalline STO, which showed substantially higher ultraviolet-driven photocurrent densities. Electrochemical impedance spectroscopy reveals large decreases in charge transfer resistance that is associated with improved performance of these films. Oxygen evolution at these electrodes was confirmed with a rotating ring-disk electrode setup. Porous versions of the STO films were investigated to evaluate the effect larger surface area can have in enhancing the water oxidation performance

Real-Time Detection of Vine Trunk for Robot Localization Using Deep Learning Models Developed for Edge TPU Devices

The concept of the Internet of Things (IoT) in agriculture is associated with the use of high-tech devices such as robots and sensors that are interconnected to assess or monitor conditions on a particular plot of land and then deploy the various factors of production such as seeds, fertilizer, water, etc., accordingly. Vine trunk detection can help create an accurate map of the vineyard that the agricultural robot can rely on to safely navigate and perform a variety of agricultural tasks such as harvesting, pruning, etc. In this work, the state-of-the-art single-shot multibox detector (SSD) with MobileDet Edge TPU and MobileNet Edge TPU models as the backbone was used to detect the tree trunks in the vineyard. Compared to the SSD with MobileNet-V1, MobileNet-V2, and MobileDet as backbone, the SSD with MobileNet Edge TPU was more accurate in inference on the Raspberrypi, with almost the same inference time on the TPU. The SSD with MobileDet Edge TPU achieved the second-best accurate model. Additionally, this work examines the effects of some features, including the size of the input model, the quantity of training data, and the diversity of the training dataset. Increasing the size of the input model and the training dataset increased the performance of the model.info:eu-repo/semantics/publishedVersio

Real-time image detection for edge devices: a peach fruit detection application

Within the scope of precision agriculture, many applications have been developed to support decision making and yield enhancement. Fruit detection has attracted considerable attention from researchers, and it can be used offline. In contrast, some applications, such as robot vision in orchards, require computer vision models to run on edge devices while performing inferences at high speed. In this area, most modern applications use an integrated graphics processing unit (GPU). In this work, we propose the use of a tensor processing unit (TPU) accelerator with a Raspberry Pi target device and the state-of-the-art, lightweight, and hardware-aware MobileDet detector model. Our contribution is the extension of the possibilities of using accelerators (the TPU) for edge devices in precision agriculture. The proposed method was evaluated using a novel dataset of peaches with three cultivars, which will be made available for further studies. The model achieved an average precision (AP) of 88.2% and a performance of 19.84 frames per second (FPS) at an image size of 640 × 480. The results obtained show that the TPU accelerator can be an excellent alternative for processing on the edge in precision agriculture.info:eu-repo/semantics/publishedVersio

Comparison of On-Policy Deep Reinforcement Learning A2C with Off-Policy DQN in Irrigation Optimization: A Case Study at a Site in Portugal

Precision irrigation and optimization of water use have become essential factors in agricul- ture because water is critical for crop growth. The proper management of an irrigation system should enable the farmer to use water efficiently to increase productivity, reduce production costs, and maxi- mize the return on investment. Efficient water application techniques are essential prerequisites for sustainable agricultural development based on the conservation of water resources and preservation of the environment. In a previous work, an off-policy deep reinforcement learning model, Deep Q-Network, was implemented to optimize irrigation. The performance of the model was tested for tomato crop at a site in Portugal. In this paper, an on-policy model, Advantage Actor–Critic, is implemented to compare irrigation scheduling with Deep Q-Network for the same tomato crop. The results show that the on-policy model Advantage Actor–Critic reduced water consumption by 20% compared to Deep Q-Network with a slight change in the net reward. These models can be developed to be applied to other cultures with high production in Portugal, such as fruit, cereals, and wine, which also have large water requirements.info:eu-repo/semantics/publishedVersio

Growth and Post-Deposition Treatments of SrTiO3 Films for Dye-Sensitized Photoelectrosynthesis Cell Applications

Sensitized SrTiO3 films were evaluated as potential photoanodes for dye-sensitized photoelectrosynthesis cells (DSPECs). The SrTiO3 films were grown via pulsed laser deposition (PLD) on a transparent conducting oxide (fluorine-doped tin oxide, FTO) substrate, annealed, and then loaded with zinc(II) 5,10,15-tris(mesityl)-20-[(dihydroxyphosphoryl)phenyl] porphyrin (MPZnP). When paired with a platinum wire counter electrode and an Ag/AgCl reference electrode these sensitized films exhibited photocurrent densities on the order of 350 nA/cm2 under 0 V applied bias conditions versus a normal hydrogen electrode (NHE) and 75 mW/cm2 illumination at a wavelength of 445 nm. The conditions of the post-deposition annealing step - namely, a high-temperature reducing atmosphere - proved to be the most important growth parameters for increasing photocurrent in these electrodes

Dye-Sensitized Nonstoichiometric Strontium Titanate Core-Shell Photocathodes for Photoelectrosynthesis Applications

A core-shell approach that utilizes a high-surface-area conducting core and an outer semiconductor shell is exploited here to prepare p-type dye-sensitized solar energy cells that operate with a minimal applied bias. Photocathodes were prepared by coating thin films of nanocrystalline indium tin oxide with a 0.8 nm Al2O3 seeding layer, followed by the chemical growth of nonstoichiometric strontium titanate. Films were annealed and sensitized with either a porphyrin chromophore or a chromophore-catalyst molecular assembly consisting of the porphyrin covalently tethered to the ruthenium complex. The sensitized photoelectrodes produced cathodic photocurrents of up to -315 μA/cm2 under simulated sunlight (AM1.5G, 100 mW/cm2) in aqueous media, pH 5. The photocurrent was increased by the addition of regenerative hole donors to the system, consistent with slow interfacial recombination kinetics, an important property of p-type dye-sensitized electrodes

Crossing the divide between homogeneous and heterogeneous catalysis in water oxidation

An atomic layer deposition (ALD) procedure is described for stabilizing surface binding of a water oxidation catalyst to the surfaces of nanostructured films of indium tin oxide. The catalyst is stabilized on the surface of electrodes by ALD of an overlayer of TiO2. Stabilization of surface binding allows use of basic solutions where a rate enhancement for water oxidation of ∼106 is observed compared with acidic conditions. There are important implications for stabilizing surface-bound molecular assemblies for applications in dye sensitized solar cells, electrocatalysis, and photoelectrocatalysis

Solar water splitting in a molecular photoelectrochemical cell

Solar water splitting into H2 and O2 with visible light has been achieved by a molecular assembly. The dye sensitized photoelectrosynthesis cell configuration combined with core–shell structures with a thin layer of TiO2 on transparent, nanostructured transparent conducting oxides (TCO), with the outer TiO2 shell formed by atomic layer deposition. In this configuration, excitation and injection occur rapidly and efficiently with the injected electrons collected by the nanostructured TCO on the nanosecond timescale where they are collected by the planar conductive electrode and transmitted to the cathode for H2 production. This allows multiple oxidative equivalents to accumulate at a remote catalyst where water oxidation catalysis occurs

Terrestrial Very-Long-Baseline Atom Interferometry: summary of the second workshop

This summary of the second Terrestrial Very-Long-Baseline Atom Interferometry (TVLBAI) Workshop provides a comprehensive overview of our meeting held in London in April 2024 (Second Terrestrial Very-Long-Baseline Atom Interferometry Workshop, Imperial College, April 2024), building on the initial discussions during the inaugural workshop held at CERN in March 2023 (First Terrestrial Very-Long-Baseline Atom Interferometry Workshop, CERN, March 2023). Like the summary of the first workshop (Abend et al. in AVS Quantum Sci. 6:024701, 2024), this document records a critical milestone for the international atom interferometry community. It documents our concerted efforts to evaluate progress, address emerging challenges, and refine strategic directions for future large-scale atom interferometry projects. Our commitment to collaboration is manifested by the integration of diverse expertise and the coordination of international resources, all aimed at advancing the frontiers of atom interferometry physics and technology, as set out in a Memorandum of Understanding signed by over 50 institutions (Memorandum of Understanding for the Terrestrial Very Long Baseline Atom Interferometer Study)

Molecular design of metal-free D–π-A substituted sensitizers for dye-sensitized solar cells

Novel donor-p-acceptor (D--A) dyes, coded as SD-1, SD-2 and SD-5, were designed and synthesized for dye-sensitized solar cells. All these dyes comprised the same donor and acceptor units while the oligo thiophene units were introduced as linkers between the donor and acceptor units. The photophysical and electrochemical properties of the dyes were investigated by UV/vis spectrometry and cyclic voltammetry. The dyes were subsequently tested as sensitizers in dye-sensitized solar cells. Photovoltaic performance of the device with SD-2 dye showed maximum monochromatic incident photon-to-current efficiency (IPCE) of 82% and an over all conversion efficiency of 6.2% under full sunlight (AM 1.5G, 100 mW cm^2) irradiation.GR-MOLP