2022 - Repozytorium publikacji - Politechnika Gdańska

Pokaż publikacje z roku

Publikacje z roku 2022

Pokaż wszystkie

Tolerance-Aware Multi-Objective Optimization of Antennas by Means of Feature-Based Regression Surrogates
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
2022 Pełny tekst IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
Assessing the immunity of antenna design to fabrication tolerances is an important consideration, especially when the manufacturing process has not been predetermined. At the same time, the antenna parameter tuning should be oriented toward improving the performance figures pertinent to both electrical (e.g., input matching) and field properties (e.g., axial ratio bandwidth) as much as possible. Identification of available trade-offs between the robustness and nominal performance can be realized through multi-objective optimization (MO), which is an intricate and computationally expensive task. This paper proposes a novel technique for fast tolerance-aware MO of antenna structures. The key component of the presented methodology is a feature-based regression surrogate, established based on the characteristic points of antenna responses extracted from its electromagnetic (EM)-simulation data, and employed for a rapid estimation of the maximum allowed input tolerance levels for given values of performance parameters of interest. Subsequent trade-off designs are generated by tuning the antenna parameters for various assumed values of relevant figures of interest (e.g., the operating bandwidth). As demonstrated using three microstrip antennas, a rendition of performance-robustness trade-off designs can be accomplished at the cost of just about forty (for six-parameter antenna) to about eighty (for fourteen-parameter antenna) per design EM analyses of the respective structure. Reliability of the approach is validated through direct EM-driven Monte Carlo analysis at the selected designs.
Tolerance-Aware Optimization of Microwave Circuits by Means of Principal Directions and Domain-Restricted Metamodels
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
- Ullah Ubaid
2022 IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
Practical microwave design is most often carried out in the nominal sense. Yet, in some cases, performance degradation due to uncertainties may lead to the system failing to meet the prescribed specifications. Reliable uncertainty quantification (UQ) is therefore important yet intricate from numerical standpoint, especially when the circuit at hand is to be evaluated using electromagnetic (EM) simulation tools. Tolerance-aware design (e.g., yield improvement) is even more challenging. This paper introduces a methodology for low-cost surrogate-based yield optimization of passive microwave components. The novelty of the proposed approach, and, at the same time, its major acceleration factor is to span the metamodel model domain with the selected principal vectors, characterized by significant response variability within operating frequency bands of the component under design. This results in a volume-wise constriction of the domain (thereby lower cost of the surrogate model setup) without restricting its size along the relevant directions of the parameter space. Consequently, our technique is a one-shot approach for yield optimization that does not require neither domain relocation nor surrogate re-construction. Our methodology is demonstrated using two microstrip components, and favorably compared to benchmark metamodeling techniques in terms of the computational cost of the yield maximization procedure. The average cost is only 130 EM simulations of the respective circuit, versus the average of 800 and over 360 analyses for the benchmark procedures. At the same time, its reliability is verified by means of EM-based Monte Carlo simulation.
Tool Wear Monitoring Using Improved Dragonfly Optimization Algorithm and Deep Belief Network
- Leo Gertrude David
- Raj Kumar Patra
- Przemysław Falkowski-Gilski
- Parameshachari Bidare Divakarachari
- Lourdusamy Jegan Antony Marcilin
2022 Pełny tekst Applied Sciences-Basel
In recent decades, tool wear monitoring has played a crucial role in the improvement of industrial production quality and efficiency. In the machining process, it is important to predict both tool cost and life, and to reduce the equipment downtime. The conventional methods need enormous quantities of human resources and expert skills to achieve precise tool wear information. To automatically identify the tool wear types, deep learning models are extensively used in the existing studies. In this manuscript, a new model is proposed for the effective classification of both serviceable and worn cutting edges. Initially, a dataset is chosen for experimental analysis that includes 254 images of edge profile cutting heads; then, circular Hough transform, canny edge detector, and standard Hough transform are used to segment 577 cutting edge images, where 276 images are disposable and 301 are functional. Furthermore, feature extraction is carried out on the segmented images utilizing Local Binary Pattern (LBPs) and Speeded up Robust Features (SURF), Harris Corner Detection (HCD), Histogram of Oriented Gradients (HOG), and Grey-Level Co-occurrence Matrix (GLCM) feature descriptors for extracting the texture feature vectors. Next, the dimension of the extracted features is reduced by an Improved Dragonfly Optimization Algorithm (IDOA) that lowers the computational complexity and running time of the Deep Belief Network (DBN), while classifying the serviceable and worn cutting edges. The experimental evaluations showed that the IDOA-DBN model attained 98.83% accuracy on the patch configuration of full edge division, which is superior to the existing deep learning models.
Topical delivery of pharmaceutical and cosmetic macromolecules using microemulsion systems
- Patrycja Szumała
- Adam Macierzanka
2022 INTERNATIONAL JOURNAL OF PHARMACEUTICS
Microemulsions are transparent, thermodynamically stable colloidal systems. Over the recent years, they have been increasingly investigated due to their potential as skin delivery vehicles for a wide range of drug molecules. The nanoscale particle size and the specificity of microemulsion components are the main features determining the skin permeation process. However, in order to effectively cross the skin barrier, the active substance itself should also meet a number of requirements, such as relatively small molecular weight, high lipophilicity with certain polarity as well as a specific partition coefficient. This review focuses on recent advancements in topical microemulsion systems related to the transport of active ingredients into the skin, including those with high molecular weight and high polarity. Selected studies have shown that permeation of therapeutic macromolecules can be increased by the correct (i.e. tailored to a specific drug) design of the microemulsion. The degree of skin penetration as well as the kinetics and the site of drug release can be controlled by appropriate qualitative and quantitative selections of penetration promoters (microemulsion components), the structure of microemulsion and its viscosity. The drug-carrier interactions can also affect the effectiveness of microemulsion formulation. These relations have been described and evaluated in this review article.
Topochemical, Single‐Crystal‐to‐Single‐Crystal [2+2] Photocycloadditions Driven by Chalcogen‐Bonding Interactions
- Jan Alfuth
- Olivier Jeannin
- Marc Fourmigué
2022 Pełny tekst ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
The face-to-face association of (E)-1,2-di(4-pyridyl)ethylene (bpen) molecules into rectangular motifs stabilized for the first time by chalcogen bonding (ChB) interactions is shown to provide photoreactive systems leading to cyclobutane formation through single-crystal-to-single-crystal [2+2] photodimerizations. The chelating chalcogen bond donors are based on original aromatic, ortho-substituted bis(selenocyanato)benzene derivatives 1–3, prepared from ortho-diboronic acid bis(pinacol) ester precursors and SeO2 and malononitrile in 75–90% yield. The very short intramolecular Se···Se distance in 1–3 (3.22–3.24 Å), a consequence of a strong intramolecular ChB interaction, expands to 3.52–3.54 Å in the chalcogen-bonded adducts with bpen, a distance (< 4 Å) well adapted to the face-to-face association of the bpen molecules into reactive position toward photochemical dimerization.
Topological extraordinary optical transmission
- Konstantinos Baskourelos
- O. Tsilipakos
- Tomasz Stefański
- S. F. Galata
- E. N. Economou
- M. Kafesaki
- Kosmas L. Tsakmakidis
2022 Pełny tekst Physical Review Research
Τhe incumbent technology for bringing light to the nanoscale, the near-field scanning optical microscope, has notoriously small throughput efficiencies of the order of 10^4-10^5 or less. We report on a broadband, topological, unidirectionally guiding structure, not requiring adiabatic tapering and, in principle, enabling near-perfect (∼100%) optical transmission through an unstructured single arbitrarily subdiffraction slit at its end. Specifically, for a slit width of just λeff/72 (λ0/138) the attained normalized transmission coefficient reaches a value of 1.52, while for a unidirectional-only (nontopological) device the normalized transmission through a λeff/21 (∼λ0/107) slit reaches 1.14; both limited only by inherent material losses, and with zero reflection from the slit. The associated, under ideal (ultralow-loss) conditions, near-perfect optical extraordinary transmission has implications, among diverse areas in wave physics and engineering, for high-efficiency, maximum-throughput nanoscopes and heat-assisted magnetic recording devices.
TOTAL CROSS SECTION MEASUREMENTS FOR ELECTRON SCATTERING ON METHYL FORMATE (HCOOCH3) MOLECULE: METHYLATION EFFECT
- Natalia Tańska
- Kuba Wójcik
- Sylwia Dylnicka
- Elżbieta Ptasińska-Denga
- Czesław Szmytkowski
- Paweł Możejko
2022 Pełny tekst PUBLICATIONS OF THE ASTRONOMICAL OBSERVATORY OF BELGRADE
We present the absolute total cross section (TCS) for electron scattering from the methyl formate (HCOOCH3) molecule measured in the 10-300 eV energy range, with electrostatic electron spectrometer working in the linear transmission mode. Comparison of TCS for the HCOOCH3 molecule with that measured earlier for the formic acid (HCOOH) compound manifests the methylation effect i.e. the response of the electron scattering dynamics on replacing of the hydrogen atom in the hydroxy group in HCOOH with the methyl group (-CH3). It is also shown that the TCS for methyl formate can be estimated with simple additivity rule, using TCSs for the formic acid, ethane and hydrogen molecules. The energy dependence of determined this way TCS for HCOOCH3 and the measured values are in very good agreement above 20 eV.
Total mercury and methylmercury (MeHg) in braised and crude Boletus edulis carpophores during various developmental stages
- Jerzy Falandysz
- Martyna Saba
- Małgorzata Rutkowska
- Piotr Konieczka
2022 Pełny tekst ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
We collected and processed Boletus edulis (King Bolete) carpophores grouped in four batches based on their developmental stage (button stage, young—white, large—white, and large—yellow). The study aimed, for the first time, to examine the B. edulis content and effect of braising and to estimate the intake of total mercury (THg) and methylmercury (MeHg) from a single meal based on whole (wet) weight (ww) and dry weight (dw). In braised carpophores, THg concentrations ranged from 0.2668 ± 0.0090 to 0.5434 ± 0.0071 mg kg−1 ww at different developmental stages, whereas crude products concentrations ranged from 0.1880 ± 0.0247 to 0.2929 ± 0.0030 mg kg−1 ww. The button stage crude carpophores were more highly contaminated with THg than at later stages of maturity, but MeHg levels were lower (p < 0.0001). On the other hand, braised button stage carpophores showed more MeHg than at later maturity stages. MeHg contributed at 1.9 ± 0.7% in THg in crude mushrooms and at 1.4 ± 0.3% in braised meals. The effect of braising was to increase the average THg and MeHg contents in fresh mushroom meals by 52 ± 31% and 53 ± 122% respectively, but a reduction of 40 ±14% and 40 ± 49% respectively was seen on a dw basis. The potential intakes of THg and MeHg from braised meals of B. edulis studied were small and considered safe.
Toward a unified model of mobile Business Intelligence (m-BI) acceptance and use
- Paweł Weichbroth
- Jolanta Kowal
- Mateusz Kalinowski
2022 Pełny tekst
Factors affecting mobile business intelligence (m-BI) acceptance and use have become an increasingly important topic in practice due to the growing complexity of organizations, and their underlying information systems (IS). Since, one can notice considerable interest in m-BI, however, to the best of our knowledge few studies (if any) aim to synthesize the existing body of knowledge with regards to the factors affecting m-BI acceptance and use. To fill this gap, we conducted a systematic literature review and summarized the current state of the art. By addressing research questions, we identified a set of five factors, namely: Perceived Value, Perceived Ease of Use, Managerial Attitudes, Facilitating Conditions and Quality of Information, and specified their inter-relationships. Moreover, we introduce an acceptance model (m-BIAM) on behavioral intention and use mobile Business Intelligence solutions. The contribution of this study lies in these evidence-based findings, which lay a solid foundation for further studies in the extent of testing and evaluating the m-BIAM model, targeted at delivering more evidence to confirm its validity and predictive power.
Towards an Understanding of the Stability Assessment of Floating Buildings
- Artur Karczewski
2022
One of the most important aspects of the design of floating facilities such as ships, floating offshore structures or floating houses is stability. Its impact on both general safety and operational aspects renders it a fundamental consideration already in preliminary design stages. Usually, the concept of sufficient stability of floating buildings is associated with the ability to keep an allowed heel angle and residual freeboard, despite the action of the heeling moment. Once in the water, a floating object has to withstand different environmental conditions. It is always acted upon by forces from various factors. The main sources of load are wind, waves and the shift of inhabitants. However, the challenges in the assessment of stability are also connected to how a floating structure responds to these sources of load and also to the method of performing a stability analysis. This paper focuses on wind load and revisits several challenges encountered in the stability calculations and in the prediction of the behavior of floating buildings. A review of the current regulations was also performed in this respect. The obtained results indicate the necessity and also direction of further considerations related to the safety of stationary floating objects.
Towards application of uncertainty quantification procedure combined with experimental procedure for assessment of the accuracy of the DEM approach dedicated for granular flow modeling
- Agata Widuch
- Marcin Nowak
- Dawid Sukiennik
- Kari Myöhänen
- Markku Nikku
- Srujal Shah
- Alessandro Parente
- Wojciech Adamczyk
2022 POWDER TECHNOLOGY
There is a high demand for accurate and fast numerical models for dense granular flows found in many industrial applications. Nevertheless, before numerical model can be used its need to be always validated against experimental data. During the validation, it is important to consider how the measurement data sets, as well as the numerical models, are affected by errors and uncertainties. In this study, the uncertainty quantification for the Discrete Element Method (DEM) model was performed based on selected quantities of interest (QOI), which were measured at a test rig. The uncertainty quantification was performed with open-source Dakota code, and the Latin hypercube sampling technique was used to determine test points. Various correlations between the input and output data were investigated to assess the impact of the possible input data errors on the output values determined by the solver. The results were validated against the measurement data from a novel in-house experimental test rig. The novel character of this work is developed procedure for study the impact of the uncertainties related with the input data on numerical results delivered by DEM model. In-house algorithm written using OpenCV libraries for determining particle motion characteristics from image dataset was used for results determination and postprocessing.
Towards azeotropic MeOH-MTBE separation using pervaporation chitosan-based deep eutectic solvent membranes
- Roberto Castro-Muñoz
- Asma Msahel
- Francesco Galiano
- Marcin Serocki
- Jacek Ryl
- Sofiane Ben Hamouda
- Amor Hafiane
- Grzegorz Boczkaj
- Alberto Figoli
2022 Pełny tekst SEPARATION AND PURIFICATION TECHNOLOGY
Deep eutectic solvents (DESs) are a new class of solvents that can offset some of the major drawbacks of common solvents and ionic liquids. When dealing with the preparation of dense membranes, the use of DESs is still challenging due to their low compatibility with the polymer phase. In this research, a novel L-proline:sulfolane (molar ratio 1:2) DES was synthesized and used for the preparation of more sustainable bio-based membranes using chitosan (CS) as a polymer phase. The compatibility among both phases (polymer and DESs) and their ability to form homogenous membranes was preliminary studied. In this regard, scanning electron and confocal microscopies were used to completely map the structure of the resulting membranes evidencing a complete homogenous structure. The membranes were also characterized in terms of contact angle (CA), Fourier transformed infrared spectroscopy (FTIR), mechanical resistance and swelling degree (uptake). Preliminary pervaporation tests for the separation of a methanol (MeOH)- methyl tert-butyl ether (MTBE) azeotropic mixture were, thus, performed. In this regard, the addition of DESs provided an enhanced separation efficiency in comparison to pristine CS membranes. Thanks to the morphology and properties exhibited, the newly developed membranes can be considered as excellent bio-based candidates to be explored in other gas selective and solvent oriented membrane operations.
Towards Carbon Neutral Settlements. The Importance of Early-Stage Urban and Energetic Optimizations
- Justyna Martyniuk-Pęczek
- Julia Kurek
- Justyna Borucka
2022 Pełny tekst ACE-Architecture City and Environment
The aim of the research was to verify the essence of interdisciplinary energy optimizations in earlystage urban design process. A further aim was to the find most optimal design variant and scenario in terms of urban energy efficiency for the future development in Nowy Port, located in Gdansk, Poland - a place requiring complex revitalization. The research combined qualitative and quantitative approaches; an urban design layer (architectural analysis of spatial systems and planning) and an energy layer (simulations). For energy and environmental simulations, the ELAS calculator was used in an innovative way, that enabled comparison of results of several projects in terms of energy demand, carbon dioxide lifecycle emissions and ecological footprint for different urban layouts. The innovative method including the application of ELAS tool in early-stage design phase proved to be relevant and allowed for an appropriate pre-assessment and comparison of urban energy efficiency parameters and life cycle analysis at an initial stage of the project. One of the key conclusions is that the design variant with the highest building density was not the most advantageous in terms of low environmental impact and energy demand. In addition, the research demonstrated that the individual behavior of residents, their mobility patterns and the energy systems are more important than the improvements focused only on building energy performance.
Towards classification of patients based on surface EMG data of temporomandibular joint muscles using self-organising maps
- Mateusz Troka
- Wiktoria Wojnicz
- Katarzyna Szepietowska
- Marek Podlasiński
- Sebastian Walerzak
- Konrad Walerzak
- Izabela Lubowiecka
2022 Pełny tekst Biomedical Signal Processing and Control
The study considers the need for an effective method of classification of patients with a temporomandibular joint disorder (TMD). The self-organising map method (SOM) was applied to group patients and used together with the cross-correlation approach to interpret the processed (rectified and smoothed by using root mean square (RMS) algorithm) surface electromyography signal (sEMG) obtained from testing the muscles (two temporal muscles and two masseters) of the temporomandibular joint (TMJ) during selected jaw movements. SOM’s Unified distance matrix (U-matrix) maps consist of formed clusters that correspond to similarities in input datasets. The results showed that SOM was able to encode muscular responses and create clusters. Information about the level of similarity between the activity of right, left, ipsilateral, and contralateral pairs of muscles was provided by intra cross-correlation coefficient (CC). A low intra CC value may indicate instability of the TMJ function. Information about the level of similarity between the sEMG signals of the same muscles tested in two different patients was provided by inter CC. SOM analysis can be used to interpret the activation of muscular systems, and by comparing the results of different individuals also to identify their TMJ health. Using the cross-correlation approach, one can find similarities in the sEMG data of different patients that can be used to provide clinically useful information. Such findings could be used to improve the clinical diagnosis of TMD and assess muscle activity during treatment.
Towards Designing an Innovative Industrial Fan: Developing Regression and Neural Models Based on Remote Mass Measurements
- Jacek Czyżewicz
- Piotr Jaskólski
- Paweł Ziemiański
- Marian Piwowarski
- Mateusz Bortkiewicz
- Krzysztof Laszuk
- Ireneusz Galara
- Marta Pawłowska
- Karol Cybulski
2022 Pełny tekst ENERGIES
This article presents the process of the construction and testing a remote, fully autonomous system for measuring the operational parameters of fans. The measurement results obtained made it possible to create and verify mathematical models using linear regression and neural networks. The process was implemented as part of the first stage of an innovative project. The article presents detailed steps of constructing a system to collect and process measurement data from fans installed in actual operating conditions and the results of analysis of this data. In particular, a measurement infrastructure was developed, defined, and implemented. Measuring equipment was mounted on selected ventilation systems with relevant fans. Systems were implemented that allowed continuous measurement of ventilation system parameters and remote transmission of data to a server where it was regularly analysed and selected for use in the process of modelling and diagnostics. Pearson’s correlation analysis for p < 0.05 indicated that all seven parameters (suction temperature, discharge temperature, suction pressure, current consumption, rotational speed, humidity, and flow) were significantly correlated with efficiency (p < 0.001). A satisfactory level of correlation between the selected parameters measured in actual conditions and the characteristics of the fan and the ventilation system was experimentally verified. This was determined by finding 4 statistically significant parameters at a confidence level of 95%. This allowed the creation of two mathematical models of the fan system and the ventilation system using linear regression and neural networks. The linear regression model showed that the suction temperature, discharge temperature, and air humidity did not affect the fan efficiency (they are statistically insignificant, p > 0.05). The neural model, which considered all measured parameters, achieved the same accuracy as the model based on four significant parameters: suction pressure, current consumption, rotational speed, and flow.
Towards evaluation of the Second Generation Intact Stability Criteria - examination of a fishing vessel vulnerability to surf-riding, based on historical capsizing
- Zbigniew Szozda
- Przemysław Krata
2022 OCEAN ENGINEERING
The Second Generation Intact Stability Criteria (SGISC) are the latest achievements in the field of intact ship stability assessment. The criteria are the result of massive international cooperative efforts and extensive research that lasted more than 15 years. Even though they are based on a solid scientific foundation, the trial period has commenced to collect user experience and further validation. One of possible approaches to evaluation of the credibility of the criteria is to demonstrate that ships which capsized in the past due to a stability failure are identified by the criteria as being vulnerable to that specific stability failure mode. The approach combines a critical analysis of the actual accident and calculations that follow procedures provided by the SGISC framework on Level 1 and Level 2. Such approach was applied to a historical catastrophe of a ship regarding the surf-riding stability failure mode. Polish flag fishing vessel m/t Cyranka, which capsized in the North Sea, has been examined for her vulnerability to the surf-riding/broaching-to phenomenon. The analysis shows that the vulnerability criteria related to surf-riding phenomenon can identify the observed vulnerability of the ship. This study contributes to the recognition of the new criteria as being reliable regarding the surf-riding. The proposed approach can be adopted for the evaluation of any stability failure mode covered by the SGISC.
Towards Knowledge Sharing Oriented Adaptive Control
- Guixian Li
- Yufeng Xu
- Haoxi Zhang
- Edward Szczerbicki
2022 Pełny tekst CYBERNETICS AND SYSTEMS
In this paper, we propose a knowledge sharing oriented approach to enable a robot to reuse other robots' knowledge by adapting itself to the inverse dynamics model of the knowledge-sharing robot. The purpose of this work is to remove the heavy fine-tuning procedure required before using a new robot for a task via reusing other robots' knowledge. We use the Neural Knowledge DNA (NK-DNA) to help robots gain empirical knowledge and introduce a Knowledge Adaption Module (KAM) utilizing the deep neural networks (DNN) for knowledge reuse. The initial experiment shows that the target robot can adapt to the inverse dynamic model of the source robot via our KAM and reuse the knowledge shared by the source robot.
Towards Open Research Data in the Economics Discipline
- Piotr Kasprzak
- Magdalena Szuflita-Żurawska
2022 Pełny tekst
Nowadays, Open Research Data, as one of the three pillars of Open Science (along with Open Access and Open Scholarly Communication), is gaining enormous attention from different academic and commercial environments. A wide range of scientific disciplines represent and produce different types of data and at the same time, gather different issues and problems in terms of sharing and dissemination research output. This chapter aims to briefly describe the current state of the scientific data for the business and economics disciplines. It presents the opportunities and concerns in those particular scientific fields where very often conducting research is supported not only by public funds but also by business and industry providers. Specific data types (such as financial data) need a particular approach to maintain them, especially in terms of the licensing, preservation and sharing openly. Their proper management can have a significant impact on the knowledge-based economy.
Towards spectral sensitivity curve for two-photon vision mechanism
- Marcin Marzejon
- Zielińska Agnieszka
- Dorota Stachowiak
- Grzegorz Soboń
- Maciej Wojtkowski
- Komar Katarzyna
2022
Abstract Purpose: The perceived brightness of different visible light sources can be compared with photometric units based on the standardized luminosity curves (300-780nm range). As reported previously (PNAS 111(50), pp. E5445-E5454 (2014)), near-infrared (NIR) radiation can cause isomerization of visual pigments by one- or two-photon absorption. The perceived color of the stimulus is red in the case of one-photon vision (1PV) or corresponds to half of the short-pulsed laser wavelength for the two-photon vision (2PV) mechanism. Since no luminosity curves for NIR range, comparison of such sources with photometric units is impossible. This study aims to provide an initial data for the 2PV spectral sensitivity curve (SSC). Methods: We measured the scotopic visibility thresholds at fovea for 4 healthy dark-adapted subjects (2 males, 2 females; 27-43 y/o) between 750-1075nm. Up to 930nm, the total visibility threshold corresponds only to 1PV mechanism. For the 810-930nm, subjects distinguished 2 thresholds: the loss of half of the wavelength hue (2PV threshold) and total visibility (1PV) threshold. Starting from 950nm, only 2PV mechanism caused the visual sensation. The stimulus was a 0.5 deg diameter flickering circle projected in the retina by scanners. Two tunable pulsed light sources: OPO (750-990nm, Frep=76MHz, τp=204fs) and fiber laser (872-1075nm, Frep=51.5MHz, τp=205±9fs) were employed for psychophysical tests. The study complied with the Declaration of Helsinki and was approved by the Ethics Committee of the Collegium Medicum, NCU. Results: The 1PV thresholds agreed with the previous works (JOSA 37(7), pp. 546-554 (1947)). Within the 810-930nm range, a relatively high standard deviation of the 2PV thresholds was observed, as finding the disappearance of half of the wavelength hue is a relatively difficult task. 2PV thresholds slightly differ for OPO and fiber laser, which is explainable by differences in pulse durations and repetition rates. For ~1040nm, the 2PV threshold values agreed to the previous authors’ results. Conclusions: The 2PV sensitivity increased with wavelength of about 1 order of magnitude (810-1075nm range). Starting from 1010 nm, the shape of the obtained 2PV SSC differs from the wavelength-doubled scotopic luminosity curve for 1PV, corrected by the eye media transmittance. The maximum of 2PV SSC was not found. The results allowed us to obtain the first approximation of the 2PV SCC shape up to 1075nm.
Towards spectroscopic monitoring of photoelectrodes: In-situ Raman photoelectrochemistry of a TiO2/prussian blue photoanode
- Konrad Trzciński
- Mariusz Szkoda
- Zuzanna Zarach
- Mirosław Sawczak
- Andrzej Nowak
2022 ELECTROCHIMICA ACTA
Here, novel in-situ Raman photoelectrochemical measurements are performed. The obtained results have proved that it is possible to track the progress of a photoelectrochemical reaction that takes place on a semiconducting electrode using the spectroscopic method. As an exemplary system, the Ti/TiO2/Prussian blue electrode is investigated. Since TiO2 is an n-type semiconductor, it cannot act as an efficient anode in dark conditions. Thus, once electrochemically reduced Prussian blue deposited on TiO2 is not reoxi- dized during anodic polarization. However, Everitt’s salt oxidation may be possible when photoexcitation of TiO2 with UV LED radiation takes place at a potential which is more anodic than the flat band poten- tial of the semiconductor. This process is successfully monitored in-situ using Raman spectroscopy. The measurements performed at different conditions allow to distinguish between processes induced by po- larization and illumination (or both). The proposed method of photoelectrode characterization through a real-time monitoring approach can be further developed and utilized for other photoelectrochemical systems.