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Exploring Mechanism of Corrosion Inhibition of WE43 and AZ31 Alloys by Aqueous Molybdate in Hank’s Solution by Multisine Impedimetric Monitoring
- Maria Osipenko
- Jakub Karczewski
- Michał Dominów
- Marta Prześniak-Welenc
- Jacek Gurgul
- Irina Kurilo
- Jacek Ryl
- Dmitry Kharitonov
2024 CORROSION SCIENCE
The concept of utilizing multisine dynamic electrochemical impedance spectroscopy to monitor effectiveness of a model molybdate inhibitor for AZ31 and WE43 Mg alloys is proposed. The corrosion kinetics and instantaneous values of inhibition efficiency (IE) of molybdate at concentrations up to 150 mM were examined. The inhibitor provides inhibition in Hank’s solution at concentrations starting from ca. 25 mM, with the IE of about 90%. These data together with results of the surface analysis allowed to propose the mechanism of the corrosion inhibition of AZ31 and WE43 Mg alloys by aqueous molybdate in Hank’s solution.
Exploring music listening patterns: an online survey
- Barbara Szyca
- Bartosz Wejda
- Marta Muchewicz
- Bożena Kostek
2024 Pełny tekst International Journal of Electronics and Telecommunications
An online survey was carried out to explore how respondents listen to music recordings. It was anticipated that the listener’s preferences would be influenced by various factors, such as age, music genre, the contexts in which they listen, and their favored methods of music consumption. Consequently, the data were collected to analyze these relationships. The survey, structured as a web application, encompassed 23 questions, with seven specifically aimed at defining the respondents and the remainder contributing to the dataset for analysis. The results reveal a prevailing preference for listening to music via streaming platforms. Respondents predominantly engage in passive listening, where music becomes a background presence without commanding their focused attention. Moreover, the data also highlight a noteworthy correlation between preferred music genres and the age of the listeners.
Exploring Neural Networks for Musical Instrument Identification in Polyphonic Audio
- Maciej Blaszke
- Grazina Korvel
- Bożena Kostek
2024 IEEE INTELLIGENT SYSTEMS
The purpose of this paper is to introduce neural network-based methods that surpass state-of-the-art (SOTA) models, either by training faster or having simpler architecture, while maintaining comparable effectiveness in musical instrument identification in polyphonic music. Several approaches are presented, including two authors’ proposals, i.e., spiking neural networks (SNN) and a modular deep learning model named FMCNN (Fully Modular Convolutional Neural Network). First, a convolutional neural network (CNN) and convolutional-recurrent neural network (CRNN), adapted from literature, are built to detect up to 13 different instruments in polyphonic music. Furthermore, FMCNN and SNN are explored. The results obtained demonstrate that both FMCNN and SNN outperform traditional CNN and CRNN in terms of accurate instrument identification. Moreover, the SNN architecture is much less complex compared to other model sizes. These findings highlight the efficacy of the methods proposed in musical instrument identification in polyphonic audio.
Exploring novel Cd(ii) complexes with 5-methyl-4-imidazolecarboxaldehyde: synthesis, structure, computational insights, and affinity to DNA through switchSense methodology
- Mateusz Kowalik
- Paulina Nowicka
- Jakub Brzeski
- Natalia Żukowska
- Joanna Masternak
- Katarzyna Kazimierczuk
- Mariusz Makowski
2024 DALTON TRANSACTIONS
A series of four Cd(II) complexes with 5-methyl-4-imidazolecarboxaldehyde (L) with different inorganic anions within or outside the coordination sphere of general formula: [CdCl2 L2 ] (1), [CdBr2 L 2] (2), [CdI2L 2] (3), and [CdL4 ](PF6 )2 ·3H2 O (4) was synthesized through one-step and two-step reactions, respectively. All complexes were obtained as colorless crystals without the need for recrystallization and exhibited solubi- lity in aqueous solutions. Structural analysis revealed different coordination environments for each complex, with variations in bond lengths and angles. The crystal packing of the complexes was stabilized by hydrogen bonding and π–π stacking interactions. FT-IR analysis indicated coordination of the ligand to the metal ion, and UV-Vis studies confirmed the stability of the complexes in solution. Computational analysis has revealed the polar nature of the complexes and their favorable stability constants. Affinity studies with DNA using the switchSense technique demonstrated rapid association and dissociation pro- cesses for all complexes, with temperature-dependent binding constants. Thermodynamic analysis suggested spontaneous with positive entropy change and endothermic formation processes for the com- plexes. Overall, the study underscores the synthesis, examination, and interaction with DNA of Cd(II ) com- plexes, demonstrating their promise within medicinal chemistry.
Exploring Relationships Between Data in Enterprise Information Systems by Analysis of Log Contents
- Łukasz Korzeniowski
- Krzysztof Goczyła
2024
Enterprise systems are inherently complex and maintaining their full, up-to-date overview poses a serious challenge to the enterprise architects’ teams. This problem encourages the search for automated means of discovering knowledge about such systems. An important aspect of this knowledge is understanding the data that are processed by applications and their relationships. In our previous work, we used application logs of an enterprise system to derive knowledge about the interactions taking place between applications. In this paper, we further explore logs to discover correspondence between data processed by different applications. Our contribution is the following: we propose a method for discovering relationships between data using log analysis, we validate our method against a real-life system running at Nordea Bank, we provide detailed insights into a real-life dataset, we analyze the influence of log quality on the results provided by our method, and we provide recommendations for developers on logging practices that can support the log analysis.
Exploring the Antitumor Efficacy of N-Heterocyclic Nitrilotriacetate Oxidovanadium(IV) Salts on Prostate and Breast Cancer Cells
- Katarzyna Chmur
- Aleksandra Tesmar
- Magdalena Zdrowowicz
- Damian Rosiak
- Jarosław Chojnacki
- Dariusz Wyrzykowski
2024 Pełny tekst MOLECULES
The crystal structures of two newly synthesized nitrilotriacetate oxidovanadium(IV) salts, namely [QH][VO(nta)(H2O)](H2O)2 (I) and [(acr)H][VO(nta)(H2O)](H2O)2 (II), were determined. Additionally, the cytotoxic effects of four N-heterocyclic nitrilotriacetate oxidovanadium(IV) salts— 1,10-phenanthrolinium, [(phen)H][VO(nta)(H2O)](H2O)0.5 (III), 2,2′-bipyridinium [(bpy)H][VO(nta)(H2O)](H2O) (IV), and two newly synthesized compounds (I) and (II)—were evaluated against prostate cancer (PC3) and breast cancer (MCF-7) cells. All the compounds exhibited strong cytotoxic effects on cancer cells and normal cells (HaCaT human keratinocytes). The structure–activity relationship analysis revealed that the number and arrangement of conjugated aromatic rings in the counterion had an impact on the antitumor effect. The compound (III), the 1,10-phenanthrolinium analogue, exhibited the greatest activity, whereas the acridinium salt (II), with a different arrangement of three conjugated aromatic rings, showed the lowest toxicity. The increased concentrations of the compounds resulted in alterations to the cell cycle distribution with different effects in MCF-7 and PC3 cells. In MCF-7 cells, compounds I and II were observed to block the G2/M phase, while compounds III and IV were found to arrest the cell cycle in the G0/G1 phase. In PC3 cells, all compounds increased the rates of cells in the G0/G1 phase.
Exploring the approaches towards support of academic entrepreneurship: evidence from an emerging market
- Marek Zinecker
- Jan Pěnčík
- Alena Kocmanová
- Tomáš Meluzín
- Adam P. Balcerzak
- Michał Pietrzak
2024 Technological and Economic Development of Economy
Over the past three decades, an exponentially growing body on elements and actors of the concept of an entrepreneurial university has emerged. Compared to its western European counterparts, however, the idea of the third role of the university has only recently been implemented in Central and Eastern European countries, and thus both research and entrepreneurial practice grapple with empirical results. In this paper, we attempt to fill this gap while adopting a case study approach to examine the issue of what resources a prominent technical university operating in the emerging market of the Czech Republic transfers to academic ventures to utilise and commercialise university research results. Within a survey, nine academic founders and two university representatives were interviewed to assess the role of university resources in facilitating academic entrepreneurship. Our research results suggest that creating infrastructure to foster the third role of universities in an emerging market is a complex and long-term issue. Formal institutions embedded in the intra-university organisational structure, such as knowledge transfer offices and entrepreneurial centres, need to be equipped with sufficient resources and competences. Skilled people with their own network of contacts to intra-university departments and external environment represented by regional incubators, venture capital providers, business angel associations, and experienced entrepreneurs should be involved in the process of creating and increasing capacity. Furthermore, the upcoming agenda should undoubtedly acknowledge the significant role of entrepreneurship education with a focus on talent recognition and entrepreneurship training to impact the entrepreneurial intentions of researchers and students. Overall, we also conclude that the motivation of academics to commercialise their inventions could be positively affected by the applied concepts of assessing their performance. Finally, this study shows that measures at all management levels have to be adopted to create a vital organisational culture that will be in alignment with the vision of entrepreneurial university. The novelty of this paper is twofold. First, the study provides a useful methodological concept of data collection as the multi-level approach was applied for studying the phenomenon of entrepreneurial university.
Exploring the Beam Squint Effects on Reflectarray Perfromance: A Comprehensive Analysis of the Specular and Scattered Reflection of the Unit Cell
- Manzoor Elahi
- Amir Altaf
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
2024 Pełny tekst SENSORS
In this article, the phenomena of beam deviation in reflectarray is discussed. The radiation pattern of the unit cell, which plays a vital role in shaping the beam of the reflectarray, is analyzed by considering undesired specular and scattered reflections. These unwanted reflections adversely affect the pattern of the single unit cell, thereby reducing the overall performance of the reflectarray. To conduct our investigations, three cases of reflectarray, i.e., (i) a center-fed with broadside beam (Case-I), (ii) a center-fed with the beam at 30∘ (Case-II), and (iii) off-center fed with the beam at 30∘ reciprocal to feed position with reference to the broadside direction (Case-III), are simulated. Different degrees of beam deviation are analyzed in each reflectarray by assessing the radiation pattern of a single element. The significance of specular reflections is further confirmed by half (left half and right half) aperture analysis of Case-II. This involves simulating the half-plane aperture illuminated by horn antenna, resulting in a distinct beam angle at the same frequency. Although the analysis specifically focuses on the three cases of the reflectarray, the proposed methodology is applicable to any type of reflectarray. The study presented in this work provides an important insight into the practical aspects of reflectarray operation, particularly in terms of quantifying undesirable effects that are normally overlooked in the design of this class of arrays. Moreover, this work holds significant potential for remote sensing satellite systems as beam deviation can adversely impact data collection accuracy and compromize observation precision, resulting in distorted images, reduced data quality, and overall hindrance to the system’s performance in capturing reliable information.
Exploring the Benefits, Challenges, and Opportunities of Collaborative Business Intelligence
- Paweł Weichbroth
- Jozef Zurada
- Celina Olszak
2024 Pełny tekst
In traditional business intelligence (BI) settings, the collective decision-making process is often hindered by the absence of knowledge and expertise exchange among various stakeholders, as well as lack of information sharing. The study delves into the concept of Collaborative BI, which aims to overcome these limitations by promoting collaboration, business networking, knowledge sharing, and improved communication among stakeholders. Based on a systematic literature review, the study explores the notion of Collaborative BI, formulates its definition, and reports on its challenges, benefits, and limitations. It also provides an insightful overview of Collaborative BI landscape and multiple advantages it can deliver to modern business organizations. The study also acknowledges potential threats to the validity of its findings due to the limited scope of the literature review. Finally, the study highlights the need for further research to address the limitations and expand our understanding of the CBI field
Exploring the potential of green chemistry in reversed-phase liquid chromatography: A review of sustainable solvents
- Oktawia Kalisz
- Marek Tobiszewski
- Alicja Nowaczyk
- Szymon Bocian
2024 TRAC-TRENDS IN ANALYTICAL CHEMISTRY
This article delves into the growing field of green analytical chemistry, focusing on sustainable solvents for reversed-phase liquid chromatography (RP LC). RP LC is a widely applied technique in the pharmaceutical, food, and environmental analysis industries, consuming vast quantities of toxic and non-renewable solvents that pose serious environmental and health risks. In response to the urgent need for greener alternatives, this review discusses organic solvents such as ethanol, innovative options such as Cyrene and dimethyl carbonate, and surfactants in micellar liquid chromatography (MLC). In addition, the potential of pure water, ionic liquids (ILs), and deep eutectic solvents (DESs) was evaluated. By analyzing the efficacy, environmental impact, and feasibility of green solvents, the review highlights their potential to replace conventional solvents, supporting safer and more sustainable analytical practices. This comprehensive and critical analysis of recent reports aims to guide future research and promote the use of green solvents in RP LC.
Exploring the role of brand experience in driving consumer emotions and engagement with sports brands in Australia
- Bruno Schivinski
- Mancuso Giulio
- Magdalena Brzozowska-Woś
2024 Pełny tekst Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska
Purpose: This paper aims to fill the theoretical gap in understanding and practical implementation by examining how sports brands in Australia use brand experience to link emotional response and brand engagement. Design/methodology/approach: The study fits into the positivist paradigm. The starting point is the stimulus-organism-response theory. A quantitative method, which is an online survey, was used to collect data. Responses from 610 respondents were collected, and after they were cleaned, data from 526 participants were analyzed. The conceptual model of the relationships between variables was verified using the regression method. Findings: The findings confirmed the hypotheses. Brands investing in comprehensive experiences effectively generate positive emotions among consumers, increasing consumer brand engagement. Research limitations/implications: The study sample was limited to the Australian population. Further limitations include the relatively small sample size and the participants' demographics skewed towards specific age ranges, which limit the potential for generalization to broader populations or industries. Future research could overcome these limitations by exploring different industries or cultural contexts and using more objective means of data collection. Practical implications: The article offers practical recommendations for creating emotionally compelling campaigns. More significant investment in experiential marketing can strengthen customer bonds and long-term relationships with sports brands. Social implications: Sports brands uniquely unite people and strongly influence communities, so sports organizations must consider the social consequences of their actions. Their actions can affect physical health and social integration, shaping values and building bonds between people. Sports organizations that consider the social aspects of their activities can build strong, positive relationships with fans, partners, and local communities. Originality/value: This article advances the understanding of experiential marketing by highlighting the importance of emotional responses in promoting strong associations between consumers and brands. The findings have implications for academics and practitioners working in advertising and brand communication more broadly in the context of the Australian sports industry.
Exploring the technological dimension of Autonomous sensory meridian response-induced physiological responses
- Sahar Seifzadeh
- Bożena Kostek
2024 PeerJ
Background In recent years, the scientific community has been captivated by the intriguing Autonomous sensory meridian response (ASMR), a unique phenomenon characterized by tingling sensations originating from the scalp and propagating down the spine. While anecdotal evidence suggests the therapeutic potential of ASMR, the field has witnessed a surge of scientific interest, particularly through the use of neuroimaging techniques including functional magnetic resonance imaging (fMRI) as well as electroencephalography (EEG) and physiological measures such as eye tracking (Pupil Diameter), heart rate (HR), heartbeat-evoked potential (HEP), blood pressure (BP), pulse rates (PR), finger photoplethysmography (PPG), and skin conductance (SC). This article is intended to provide a comprehensive overview of technology’s contributions to the scientific elucidation of ASMR mechanisms. Methodology A meticulous literature review was undertaken to identify studies that have examined ASMR using EEG and physiological measurements. The comprehensive search was conducted across databases such as PUBMED, SCOPUS, and IEEE, using a range of relevant keywords such as ‘ASMR’, ‘Autonomous sensory meridian response’, ‘EEG’, ‘fMRI’, ‘electroencephalography’, ‘physiological measures’, ‘heart rate’, ‘skin conductance’, and ‘eye tracking’. This rigorous process yielded a substantial number of 63 PUBMED and 166 SCOPUS-related articles, ensuring the inclusion of a wide range of high-quality research in this review. Results The review uncovered a body of research utilizing EEG and physiological measures to explore ASMR’s effects. EEG studies have revealed distinct patterns of brain activity associated with ASMR experiences, particularly in regions implicated in emotional processing and sensory integration. In physiological measurements, a decrease in HR and an increase in SC and pupil diameter indicate relaxation and increased attention during ASMR-triggered stimuli. Conclusions The findings of this review underscore the significance of EEG and physiological measures in unraveling the psychological and physiological effects of ASMR. ASMR experiences have been associated with unique neural signatures, while physiological measures provide valuable insights into the autonomic responses elicited by ASMR stimuli.
Exploring the trends in flux-cored arc welding: scientometric analysis approach
- Aleksandra Świerczyńska
- Balázs Varbai
- Chandan Pandey
- Dariusz Fydrych
2024 Pełny tekst INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
Flux-cored arc welding (FCAW) is a universal group of welding methods in terms of the scope of application and automation possibilities, the share of which in various industries in many countries is still increasing. The paper presents the results of bibliographic analyses (scientometric analysis with the use of VOSviewer, Bibliometrix and CitNetExplorer tools) of a data set of 993 publications indexed in the Web of Science database on the subject of FCAW for all types of flux-cored wires. An objective and unbiased approach to analysis resulted in a relatively neutral assessment of the state of knowledge in the field of FCAW and allowed for the identification of research directions carried out in the world, the dynamics of their changes as well as research gaps and needs. The scientometric analysis approach provided a holistic picture of the development of FCAW over the last 58 years, pointing to the geographical areas where this process has been and is most intensively researched, the agencies funding this research, the most active research teams, as well as the journals that have most often published articles on this topic. The most current research directions in relation to FCAW include underwater welding, hardfacing and cladding purposes, health and safety issues, and more general topic: properties and weldability of ferrous alloys. However, among the most urgent research needs the following topics: fatigue analysis of welded joints, environmental degradation of flux-cored wires, properties and weldability of nickel alloys, development of hybrid and combined welding procedures can be listed.
Exposure to cooking emitted volatile organic compounds with recirculating and extracting ventilation solutions
- Wojciech Wojnowski
- Aileen Yang
- Tomas Mikoviny
- Armin Wisthaler
- Kari Thunshelle
2024 Pełny tekst BUILDING AND ENVIRONMENT
Energy-efficient urban development leads to the compact design of apartments. Recirculating ventilation solutions are an attempt to minimize the space required for ventilation ducting, but more data on their performance are needed. Cooking is a major source of volatile organic compounds (VOCs) emissions. It is necessary to assess how well recirculating kitchen hoods perform in reducing the residents' exposure to cooking fumes compared to extracting hoods, and what airflow rates assure good removal efficiency. We have monitored the occupant exposure to several VOCs generated during the cooking of a model meal under different ventilation scenarios in a purpose-built test kitchen resembling the layout of a modern, open-space apartment. Time-resolved VOC emission profiles were measured using a proton transfer reaction time-of-flight mass spectrometer. The performance of activated carbon sorption-based filters for recirculating kitchen hoods in the removal of selected VOCs was also assessed. Alcohols, particularly ethanol, dominated emissions from cooking a typical Norwegian meal, but they also included acetaldehyde, acetone, carboxylic acids, and trimethylamine, among others. The use of recirculating kitchen hoods led to, on average, higher occupant exposure to VOCs compared to extracting kitchen hoods during and after cooking. This was in part due to the poor ethanol removal efficiency of the recirculating ventilation's air filters.
Extending loophole-free nonlocal correlations to arbitrarily large distances
- Anubhav Chaturvedi
- Giuseppe Viola
- Marcin Pawłowski
2024 Pełny tekst npj Quantum Information
Quantum theory allows spatially separated observers to share nonlocal correlations, which enable them to accomplish classically inconceivable information processing and cryptographic feats. However, the distances over which nonlocal correlations can be realized remain severely limited due to their high fragility to noise and high threshold detection efficiencies. To enable loophole- free nonlocality across large distances, we introduce Bell experiments wherein the spatially separated parties randomly choose the location of their measurement devices. We demonstrate that when devices close to the source are perfect and witness extremal nonlocal correlations, such correlations can be extended to devices placed arbitrarily far from the source. To accommodate imperfections close to the source, we demonstrate an analytic trade-off: the higher the loophole-free nonlocality close to the source, the lower the threshold requirements away from the source. We utilize this trade-off and formulate numerical methods to estimate the critical requirements of individual measurement devices in such experiments.
External electron donor and transporter of iron triggers the paths to enhancing collaboration of anammox and denitrification in granular sludge: Bacterial resilience and synergetic promotion mechanism
- Meihui Tang
- Rui Duan
- Xiangchen Li
- Jacek Mąkinia
- Shenbin Cao
- Yongzhen Peng
2024 CHEMICAL ENGINEERING JOURNAL
Autotrophic nitrogen removal via anaerobic ammonium oxidation (anammox) technology currently faces sig nificant challenges in treating low-strength wastewater due to inefficient retention of bacteria and unstable activity under fluctuating conditions. This study demonstrates enhanced resilience and stability of anammox coupled with partial denitrification (PD) in granular sludge, assisted by ferric iron (Fe(III)) and nano zero-valent iron (nZVI). The systems treated wastewater with low concentrations of ammonia (NH4 +-N of 50 ~ 80 mg/L) and nitrate (NO3 − -N of 60 ~ 100 mg/L). Fe(III) and nZVI were intermittently added to two PD coupled with anammox (PD/A) systems, which were subjected to increasing nitrogen loading rates (NLRs) and decreasing temperature. Remarkably, both Fe(III)- and nZVI-assisted systems achieved satisfactory total nitrogen (TN) removal effi ciencies of 98.1 % and 96.6 %, respectively, even as the temperature dropped from 28.5℃ to 13.4℃ and the NLR increased from 0.22 to 0.72 kgN/m3 /d. Significantly, these two systems exhibited pronounced resilience under the shocking effect of excessive organic load, extremely low pH, and high salinity. The presence of iron, acting as an accelerated electron transporter, enhanced anammox activity and microbial NH4 +-N oxidation. Additionally, iron reduced the requirement for an organic carbon source, further stimulating the competitiveness of anammox for nitrite (NO2 − -N) against denitrification. Interestingly, metagenomic analysis revealed that the functional bacteria Thauera, responsible for PD, employed versatile metabolic pathways for NO3 − -N reduction to NO2 − -N using Fe(II) as an electron donor. Overall, this study provides new insights into microbial interactions and versatile metabolism in iron-assisted anammox systems, contributing to more energy-efficient wastewater treatment.
Extraction pathways and purification strategies towards carminic acid as natural-based food colorant: A comprehensive review
- Dante Ferreyra-Suarez
- Leonardo Paredes-Vargas
- Seid Mahdi Jafari
- Octavio García-Depraect
- Roberto Castro Munoz
2024 ADVANCES IN COLLOID AND INTERFACE SCIENCE
As a current trend of fabricating healthier products, food manufacturing companies seek for natural-based food colorant aiming to replace the synthetic ones, which apart from meeting sensorial and organoleptic aspects, they can also act as health promoters offering additional added value. Carminic acid is a natural based food colorant typically found in several insect taxa. However, there are current approaches which pursue the production of this natural pigment via biotechnological synthesis. To date, this colorant has been intensively applied in the manufacture of several food items. Unfortunately, one of the main limitations deals with the establishment of the right protocol of extraction and purification of this component since there is no report analyzing the main extraction techniques for obtaining carminic acid. Therefore, this review, for the first time, comprehensively analyzes the ongoing strategies and protocols proposed by scientists towards either extraction or purification of carminic acid from its origin source, and from biotechnological systems. Emphasis has been focused on the main findings dealing with extraction techniques and the relevant insights in the field. A detailed discussion is provided on the advantages and drawbacks of the reported extraction and purification methods, main solvents used and their key interactions with target molecules.
Extra-curricular project-oriented education in optoelectronics in the Faculty of Electronics, Telecommunications and Informatics at Gdańsk University of Technology, Poland
- Adam Mazikowski
- Paweł Wierzba
2024 Global Journal of Engineering Education
Project-oriented education constitutes a key part of the curriculum in the Faculty of Electronics, Telecommunications and Informatics of Gdańsk University of Technology (Gdańsk Tech), Poland. Students on the Engineer and Master of Science level studies take part in several projects, both individually and in teams. In addition to compulsory activities, students have the opportunity to take part in the activities of student scientific chapters of international professional societies, such as SPIE or Optica, as well as in scientific research projects, in particular financed by Gdańsk Tech in the framework of its Technetium and Plutonium programmes. In this article, the authors present the framework and implementation of these projects. Opportunities, limitations and threats in the projects in optoelectronics are discussed, based on selected cases. Results of example projects are outlined, and modifications to the process are formulated.
Fabrication of Gold and Silver Nanoparticles Supported on Zinc Imidazolate Metal–Organic Frameworks as Active Catalysts for Hydrogen Release from Ammonia Borane
- Elibe S. Souza
- Maria Alaide de Oliveira
- Jildimara de Jesus Santana
- Natalia Łukasik
- Ohanna Maria Menezes Madeiro da Costa
- Luciano Costa Almeida
- Bráulio Barros
- Joanna Kulesza
2024 ACS Omega
Well-dispersed Au and Ag nanoparticles (NPs) have been immobilized on a zinc imidazolate metal−organic framework, Zn(mim), using the “one-pot” method and tested as catalysts in ammonia borane hydrolysis. The AuNPs@Zn(mim) and AgNPs@Zn(mim) materials were characterized by FTIR, XRD, ICP-OES, TGA, BET, SEM, and TEM. The AgNPs@Zn(mim) catalyst showed a high yield (98.5%) and high hydrogen generation rate (3352.71 mL min−1 gAg−1) in NH3BH3 dehydrogenation. The determined activation energies (19.6 kJ mol−1 for AuNPs@Zn(mim) and 38.13 kJ mol−1 for AgNPs@Zn(mim)) are lower than those for most reported catalysts containing Au/Ag-MOF used in the hydrolysis of NH3BH3. Moreover, the catalysts tested here revealed good stability and reusability, preserving 71.42% (AuNPs@Zn(mim)) and 88.23% (AgNPs@Zn(mim)) of their initial catalytic activities after five consecutive cycles. In the case of AgNPs@Zn(mim), the combination of the simple and green synthesis method, low active metal content, relatively low cost, and moderate dehydrogenation conditions makes the material an excellent candidate to produce hydrogen from ammonia borane.
Fabrication of high-density nitrogen-vacancy (NV) center-enriched diamond particles through methyl trityl amine (C20H19N) seeding
- Srinivasu Kunuku
- Mateusz Ficek
- Saravanan Sengottuvel
- Jacek Ryl
- Mariusz Mrózek
- Aneta Lewkowicz
- Adam M. Wojciechowski
- Robert Bogdanowicz
2024 DIAMOND AND RELATED MATERIALS
Diamond particles (DPs) show promise for advanced applications in bioimaging and quantum sensing due to the presence of defect centers. This work reports a unique growth process for diamond particles composed of nitrogen-vacancy centers (NV-DPs) using a methyl trityl amine (C20H19N) diamondoid seed, which acts as a nitrogen source for NV creation. Growth was performed via microwave plasma-assisted chemical vapor deposition in a CH4/H2 plasma. Tantalum plates were chosen as the substrate to facilitate the release of the NV-rich DPs after growth. Raman spectra of NV-DPs grown at 550 °C showed a sharp, intense peak at ~1334 cm−1, while those grown at 750 °C exhibited a broader, high intensity peak at 1336 cm−1. Photoluminescence revealed the formation of high-density NV centers, with the highest intensity for NV-DPs grown at 750 °C and 20 Torr. Optically detected magnetic resonance confirmed the presence of NV centers, especially for DPs grown at 750 °C. This seeding process enables precise nitrogen incorporation into diamond crystals to generate required spin properties by growing high-quality, well-faceted NV-DPs with customizable NV densities.