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  • Scale transformations in model exchange potentials in low energy electron-atom scattering
    • Felipe Arretche
    • Eliton Popovicz Seidel
    • Wagner Tenfen
    2024 JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA

    Model exchange potentials are particularly interesting to account for the indistinguishability between the projectile and target electrons in electron-atom scattering in vacuo and plasma environments. It is well known that their performance is pretty satisfactory in the high energies but also that discrepancies from the results obtained with exact exchange are found toward the zero energy limit. In this article, we examine how well established model exchange potentials based on the free electron gas approach compare to phase shifts calculated considering exchange in exact form. In particular, we show that the Hara and the semiclassical exchange potentials are able to reproduce reference low energy phase shifts through a simple scale transformation, in opposition to the previous approaches where energy dependent corrections to the local momentum were adopted. We provide the scale factors and phase shifts for electron scattering by He, Ne and Ar atoms for < 1,0 a.u. Such scaling factors can be determined reproducing the scattering length and the number of s-wave bound states from exact exchange calculations. We also show that the scaling procedure works for electronic densities that present the physically correct asymptotic behavior. The present results are important to the research field, since they form the basis to construction of scattering models based on optical potential approaches.

  • Schemat powstawania rys na przykładzie osiowo rozciąganego pręta żelbetowego
    • Marek Wesołowski
    • Maciej Solarczyk
    2024 Pełny tekst Inżynieria i Budownictwo

    W artykule przedstawiono w sposób schematyczny ideę powstawania kolejnych rys w konstrukcjach żelbetowych na przykładzie osiowo rozciąganego pręta. Opisano początkowy oraz końcowy stan zarysowania. Wyprowadzono wzór na szerokość rysy. Przedstawiono interpretację geometryczną rys dla fazy początkowego zarysowania oraz efekt tension stiffening na przykładzie elementu osiowo rozciąganego. Przedstawiono przykładowe obliczenia miary efektu tension stiffening, szerokości rys oraz średnich naprężeń przyczepności dla fazy początkowych rys.

  • Schottky Junction-Driven Photocatalytic Effect in Boron-Doped Diamond-Graphene Core–Shell Nanoarchitectures: An sp3/sp2 Framework for Environmental Remediation
    • Surya Kanta Ghadei
    • Mateusz Ficek
    • Salila Kumar Sethy
    • Jacek Ryl
    • Mukul Gupta
    • Ramasamy Sakthivel
    • Kamatchi J Sankaran
    • Robert Bogdanowicz
    2024 ACS Applied Materials & Interfaces

    Self-formation of boron-doped diamond (BDD)-multilayer graphene (MLG) core–shell nanowalls (BDGNWs) via microwave plasma-enhanced chemical vapor deposition is systematically investigated. Here, the incorporation of nitrogen brings out the origin of MLG shells encapsulating the diamond core, resulting in unique sp3/sp2 hybridized frameworks. The evolution mechanism of the nanowall-like morphology with the BDD-MLG core–shell composition is elucidated through a variety of spectroscopic studies. The photocatalytic performance of these core–shell nanowalls is examined by the deterioration of methylene blue (MB) and rhodamine B (RhB) dyes beneath low-power ultraviolet (UV) light irradiation. Starting with 5 ppm dye solutions and employing BDGNWs as the photocatalyst, remarkable degradation efficiencies of 95% for MB within 100 min and 91% for RhB within 220 min are achieved. The effect of varying dye concentrations was also examined. The enhanced photocatalytic activity is driven by carrier photogeneration and mediated by the Schottky junction formed between BDD and MLG, promoting efficient photoinduced charge separation. The stability of the BDGNW photocatalyst is examined, and after five test runs, the photocatalytic behavior for MB and RhB degradation decreases to 87 and 85%, respectively, from initial values of 96 and 91%, demonstrating excellent photostability. These findings underscore the significance of diamond-graphene nanoarchitectures as promising green carbonaceous photocatalysts.

  • Screening evaluation of the quality of commercially available cigars, cigarillos, and bidis based on emission levels of selected terpenes and terpenoids
    • Mariusz Marć
    • Sylwia Bednarska
    • Paweł Hać
    • Piotr Konieczka
    2024 MICROCHEMICAL JOURNAL

    The aim of the research was to verify the use of the solvent-free, non-destructive and easy to operate analytical method to study and compare the emissions of 16 representatives of terpenes and terpenoids from commercially available cigars, cigarillos and bidis − a potential screening analysis for the quality of combustible tobacco products. To assess the amount of organic compounds emitted to the gaseous phase from investigated tobacco samples, the stationary emission chambers system (at the sample conditioning stage) and gas chromatography with flame ionization detector (at the final analyte determination stage) were used. Studied samples represented five origins: the Dominican Republic, Nicaragua, Mexico, Cuba, and India and two manufacture approaches: machine-made and handmade. The assessed values of total volatile organic compounds (TVOCs) was from 0.58 to 28 µg·g−1 (at 60 °C) and from 26 to 430 µg·g−1 (at 120 °C). For Dominican products, Camphene and α-Cedrene were characterized by the highest emission level (233 ± 34 ng·g−1 and (3.7 ± 1.4) × 102 ng·g−1, respectively). In a case of Mexican and Cuban products it was noticed that the emission level of determined terpenes and terpenoids is higher in the case of hand-rolled tobacco products than mechanically manufactured ones. In a case of Nicaraguan hand-rolled products, Camphene, L-(−)-Fenchone, and α-Cedrene were characterized by the highest emission rate at 120 °C (213 ± 81 ng·g−1, 191 ± 45 ng·g−1 and 213 ± 84 ng·g−1, respectively). The highest emission level for Indian products in 120 °C was observed for α-Cedrene and Geranyl Acetate – respectively 181.6 ± 4.4 ng·g−1 and 101 ± 13 ng·g−1. The results of this study may indicate that sometimes cheaper products such as cigarillo have an emission profile that classifies them between expensive products such as “large cigars.”

  • Screening of perfluoroalkyl substances and their environmental impact in sequencing batch reactors combined with nature-based solutions
    • Grażyna Gałęzowska
    • Katarzyna Kołecka
    • Monika Cieszyńska-Semenowicz
    • Vladyslaw Redko
    • Magdalena Gajewska
    2024 Pełny tekst ECOLOGICAL ENGINEERING

    Perfluoroalkyl substances (PFAS) are a growing problem in the environment. The research indicates that they are present in surface water, groundwater, drinking water sources, wastewater treatment plant (WWTP) effluents, and landfill leachates. Additionally, the conventional methods of wastewater treatment are ineffective in their removal. This study aimed to indicate the concentration of PFAS in wastewater during treatment processes in sequential biological reactors (SBRs), followed by two ponds working in series. Samples were collected after individual stages of treatment, during the beginning of touristic seasonality. The research also determined the environmental impact of the PFAS by determining the ecotoxicity and performing a risk assessment of the analyzed wastewater. The analyzed wastewater samples were collected from the different stages of the WWTP in Swarzewo, which uses SBRs. In the collected samples, basic parameters such as total suspended solids (TSS), biological oxygen demand (BOD5), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), as well as identification and concentrations of PFAS were determined. Based on this data, an ecotoxicological assessment and risk assessment of the wastewater was performed. The research indicated that the basic parameters and Microtox toxicity assay are not sensitive to changes in the PFAS content in wastewater. As the hydrophobicity of the PFAS increases, their solubility in the water decreases. However, these substances may still be present in suspended particles, leading to an increase in their global concentration in the water and, consequently, may pose environmental hazards. The proposed technology of wastewater treatment is an effective PFAS retention system in the sediment (removal of over 90 %). Meteorological conditions affect the PFAS transformation processes taking place in SBRs.

  • Screening stability, thermochemistry, and chemical kinetics of 3-hydroxybutanoic acid as a bifunctional biodiesel additive
    • Mohamed A. Abdel-Rahman
    • Abolfazl Shiroudi
    • Jacek Czub
    • Hao Zhao
    2024 Pełny tekst JOURNAL OF PHYSICAL CHEMISTRY A

    The thermo-kinetic aspects of 3-hydroxybutyric acid (3-HBA) pyrolysis in the gas phase were investigated using density functional theory (DFT), specifically the M06-2X theoretical level in conjunction with the cc-pVTZ basis set. The obtained data were compared with benchmark CBS-QB3 results. The degradation mechanism was divided into 16 pathways, comprising 6 complex fissions and 10 barrierless reactions. Energy profiles were calculated and supplemented with computations of rate coefficients and branching ratios over the temperature range of 600–1700 K at a pressure of 1 bar using transition state theory (TST) and Rice–Ramsperger–Kassel–Marcus (RRKM) methods. Thermodynamics results indicated the presence of six stable conformers within a 4 kcal mol–1 energy range. The estimated chemical kinetics results suggested that TST and RRKM approaches are comparable, providing confidence in our calculations. The branching ratio analysis reveals that the dehydration reaction pathway leading to the formation of H2O and CH3CH═CHCO2H dominates entirely at T ≤ 650 K. At these temperatures, there is a minor contribution from the simple homolytic bond fission reaction, yielding related radicals [CH3•CHOH + •CH2CO2H]. However, at T ≥ 700 K, this reaction becomes the primary decomposition route. At T = 1700 K, there is a minor involvement of a reaction pathway resulting in the formation of CH3CH(OH)•CH2 + •CHO(OH) with an approximate contribution of 16%, and a reaction leading to [•CH3 + •CH2OHCH2CO2H] with around 9%.

  • Segmentation-Based BI-RADS ensemble classification of breast tumours in ultrasound images
    • Maciej Bobowicz
    • Mikołaj Badocha
    • Katarzyna Gwozdziewicz
    • Marlena Rygusik
    • Paulina Kalinowska
    • Edyta Szurowska
    • Tomasz Dziubich
    2024 Pełny tekst INTERNATIONAL JOURNAL OF MEDICAL INFORMATICS

    Background: The development of computer-aided diagnosis systems in breast cancer imaging is exponential. Since 2016, 81 papers have described the automated segmentation of breast lesions in ultrasound images using arti- ficial intelligence. However, only two papers have dealt with complex BI-RADS classifications. Purpose: This study addresses the automatic classification of breast lesions into binary classes (benign vs. ma- lignant) and multiple BI-RADS classes based on a single ultrasonographic image. Achieving this task should reduce the subjectivity of an individual operator’s assessment. Materials and Methods: Automatic image segmentation methods (PraNet, CaraNet and FCBFormer) adapted to the specific segmentation task were investigated using the U-Net model as a reference. A new classification method was developed using an ensemble of selected segmentation approaches. All experiments were performed on publicly available BUS B, OASBUD, BUSI and private datasets. Results: FCBFormer achieved the best outcomes for the segmentation task with intersection over union metric values of 0.81, 0.80 and 0.73 and Dice values of 0.89, 0.87 and 0.82, respectively, for the BUS B, BUSI and OASBUD datasets. Through a series of experiments, we determined that adding an extra 30-pixel margin to the segmentation mask counteracts the potential errors introduced by the segmentation algorithm. An assembly of the full image classifier, bounding box classifier and masked image classifier was the most accurate for binary classification and had the best accuracy (ACC; 0.908), F1 (0.846) and area under the receiver operating char- acteristics curve (AUROC; 0.871) in the BUS B and ACC (0.982), F1 (0.984) and AUROC (0.998) in the UCC BUS datasets, outperforming each classifier used separately. It was also the most effective for BI-RADS classification, with ACC of 0.953, F1 of 0.920 and AUROC of 0.986 in UCC BUS. Hard voting was the most effective method for dichotomous classification. For the multi-class BI-RADS classification, the soft voting approach was employed. Conclusions: The proposed new classification approach with an ensemble of segmentation and classification approaches proved more accurate than most published results for binary and multi-class BI-RADS classifications.

  • Seismic probabilistic assessment of steel and reinforced concrete structures including earthquake-induced pounding
    • Farzin Kazemi
    • Neda Asgarkhani
    • Ahmed Manguri
    • Robert Jankowski
    2024 Pełny tekst Archives of Civil and Mechanical Engineering

    Recent earthquakes demonstrate that prioritizing the retrofitting of buildings should be of the utmost importance for enhancing the seismic resilience and structural integrity of urban structures. To have a realistic results of the pounding effects in modeling process of retrofitting buildings, the present research provides seismic Probability Factors (PFs), which can be used for estimating collision effects without engaging in intricate and time-intensive analysis. To include the low-, to mid-rise buildings, the 3-Story, 5-Story, and 9-Story adjacent steel and Reinforced Concrete (RC) moment-resisting frames were modeled in OpenSees software capable to take into account the structure in a state of collapse during the analysis, which can provide the real condition of buildings under seismic excitations. Results of analysis confirmed that the impact force can considerably affect the moment–rotation curve of beams and columns, in which, it can affect the structural response of structures during earthquakes. Therefore, seismic PFs proposed to examine the possibility of changes in the performance levels and fragility assessments. Moreover, proposed PFs can be used as coefficient factors to facilitate the retrofitting process of buildings and improve the environmental effects.

  • Seismic response and performance prediction of steel buckling-restrained braced frames using machine-learning methods
    • Neda Asgarkhani
    • Farzin Kazemi
    • Anna Jakubczyk-Gałczyńska
    • Benyamin Mohebi
    • Robert Jankowski
    2024 Pełny tekst ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE

    Nowadays, Buckling-Restrained Brace Frames (BRBFs) have been used as lateral force-resisting systems for low-, to mid-rise buildings. Residual Interstory Drift (RID) of BRBFs plays a key role in deciding to retrofit buildings after seismic excitation; however, existing formulas have limitations and cannot effectively help civil engineers, e.g., FEMA P-58, which is a conservative estimation method. Therefore, there is a need to provide a comprehensive tool for estimating seismic responses of Interstory Drift (ID) and RID with novel approaches to fulfill the shortcomings of existing formulas. The Machine Learning (ML) method is an interdisciplinary approach that makes it possible to solve these types of engineering problems. Therefore, the current study proposes ML algorithms to provide a prediction model for determining the seismic response, seismic performance curve, and seismic failure probability curve of BRBFs. To train ML-based prediction models, Nonlinear Time-History Analysis (NTHA) and Incremental Dynamic Analysis (IDA) were performed on the 2-, to 12-Story BRBFs subjected to 78 far-field ground motions, and 606944 data points were prepared for different prediction purposes. The results indicate that the considered approaches are justified. For instance, the proposed ML methods have the ability to predict the maximum ID, maximum RID and maximum roof ID with the accuracy of even 98.7%, 95.2%, and 93.8%, respectively, for the 4-Story BRBF. Moreover, a general preliminary estimation tool is introduced to provide predictions based on the input parameters considered in the study.

  • Selected aspects of performance of organic Rankine cycles incorporated into bioenergy with carbon capture and storage using gasification of sewage sludge
    • Kamil Stasiak
    • Paweł Ziółkowski
    • Dariusz Mikielewicz
    2024 Pełny tekst JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME

    The study aims to investigate the application of the Organic Rankine Cycle (ORC) in the bioenergy with carbon capture and storage (BECCS) using gasification of sewage sludge. The tool used in the investigation is the Aspen Plus software with REFPROP property methods for calculating fluid properties. The reason for this study is that a detailed analysis of the proposed BECCS process flow diagram indicates that a certain amount of waste heat is available in the exhaust gas from the high-to-intermediate pressure gas turbine. Some of this energy can be used by applying expansion in a low-pressure turbine, optionally by applying of regenerative water heating, which is then redirected to the combustion chamber, or finally by incorporating the ORC into the main cycle. For the ORC cycle, different configurations are studied, with regeneration and using different working fluids. For the highest efficiency of the cycle, the regenerative heating of high-pressure water is applied and a suitable ORC working fluid with optimal saturation parameters and mass flow is selected. Such modified proposed BECCS power plant hybrid systems with ORC are compared to the reference case with lower pressure expansion. A study of the heat duty and temperature distribution in heat exchangers is carried out. Five ORC fluids were investigated, namely ethanol, refrigerants R236-ea, R245-fa, R1233zd(E) and water, which gave a net efficiency of the whole power plant of 39.71%, 40.02%, 40.26%, 40.34% and 39.35% respectively, while the proposed BECCS reference case gave 38.89%.

  • Selected aspects of the operation of Dual Active Bridge DC/DC converters
    • Serafin Bachman
    • Marek Turzyński
    • Marek Jasinski
    2024 Pełny tekst Bulletin of the Polish Academy of Sciences-Technical Sciences

    This review paper discusses the concept of a bidirectional dual active bridge (DAB) DC/DC converter. Practical applications and control methods are explored, and various types of DAB converters are introduced and characterized. Aspects of operation are discussed, and enriched by the results of theoretical analyses, simulations, and experimental measurements of the original authors’ work.

  • Selected symmetrically substituted carbazoles: Investigation of anticancer activity and mechanisms of action at the cellular and molecular levels
    • Mateusz Olszewski
    2024 Pełny tekst

    DNA topoisomerases play a critical role as essential enzymes in controlling alterations in the topology of DNA. They achieve this by orchestrating the coordinated process of breaking and rejoining DNA strands, which is crucial for maintaining the proper structure of DNA during regular cellular development. The search for and development of new potential anticancer drugs is a challenging yet immensely important area of research that can contribute significantly to advancements in the treatment and combat of cancer-related diseases. In the scope of my doctoral work, research was conducted on three heterocyclic compounds derived from carbazole, aiming to identify their anticancer mechanism of action. The studies demonstrated that these compounds act as non-intercalating DNA inhibitors of human topoisomerase I and IIα. Among the three investigated compounds, 36a exhibited notably higher inhibitory activity against the IIα isoform compared to IIβ. Additionally, their cytotoxic and antiproliferative properties were determined, along with their ability to inhibit tyrosine protein kinases and induce cell death. The conducted experiments allowed to determine the main mechanisms of action of these anticancer compounds, which could in the future contribute to the design and synthesis of new potential drug candidates.

  • Selecting a transport and forwarding company for meeting a customer’s needs when organizing international road cargo transportation
    • Ievgenii Lebid
    • Nataliia Luzhanska
    • Iryna Lebid
    • Alexander Mazurenko
    • Inesa Halona
    • Kateryna Kovtsur
    • Tetiana Yarmak
    • Tetiana Sotnikova
    • Ievgen Medvediev
    2024 Pełny tekst Eastern-European Journal of Enterprise Technologies [ Восточно-Европейский журнал передовых технологий ]

    The object of this study is the process of planning the work of a manufacturing enterprise that needs transport and forwarding services when exporting goods to counterparties in different countries of the world. The problem being solved is predetermined by the need to devise recommendations for choosing a transport and forwarding company when serving an individual customer, based on its individual needs and conditions of cooperation. A simulation model for the selection of a transport and forwarding company was constructed and implemented to meet the customer’s needs when exporting goods, applying the GPSS World simulation automation package. The model provides for the optimization of the choice of a transport and forwarding company for servicing counterparties based on the assessment of their activity indicators over previous periods of cooperation. When building the model, the types of commercial conditions of the exporter’s cooperation with the transport and forwarding company, indicators of the quality assessment of the basic level of service and the duration of service at all stages of the foreign trade operation were taken into account. The application of the constructed model in practice will enable exporters and importers to choose a transport and forwarding company depending on the individual needs of customers in the delivery of goods. The simulation results reflect the performance indicators of the provision of transport and forwarding services by various specialized enterprises. This will make it possible to involve in the transport and forwarding service of a separate counterparty an organization that will meet all the requirements of goods buyer in accordance with the terms of the international economic contract. At the same time, the duration of choosing and agreeing the terms of cooperation could be reduced by 12–15 % while the efficiency of transport and forwarding services would increase by 13–16 %.

  • Selective H2 production from plastic waste through pyrolysis and in-line oxidative steam reforming
    • Mayra Suarez
    • Katarzyna Januszewicz
    • Maria Cortazar
    • Lopez Gartzen
    • Laura Santamaria
    • Martin Olazar
    • Maite Artetxe
    • Maider Amutio
    2024 Pełny tekst ENERGY

    This study deals with the proposal of pyrolysis and in-line oxidative steam reforming (P-OSR) for plastic waste valorization and assesses the potential of this strategy for the selective production of H2. Overall, the study aims at progressing towards the fine-tuning of the pyrolysis-reforming technology by co-feeding O2. Thus, a multi-point O2 injection system has been developed to ensure a suitable O2 distribution in the reforming reactor and avoid the formation of hot spots, as they may cause catalyst deactivation by metal sintering. Moreover, as O2 is directly supplied into the catalytic bed, pre-combustion of the volatile stream before contacting the catalyst is avoided and in-situ coke combustion is promoted. The P-OSR of HDPE was carried out in a two-step reaction system, which combines CSBR (conical spouted bed reactor) and FBR (fluidized bed reactor) technologies. The experiments were conducted in continuous mode and the influence of the main process conditions at zero time on stream was analyzed. Thus, the effect of reforming temperature was studied in the 550–750 °C range, that of the space time from 3.12 to 15.62 gcat min gHDPE−1, steam to plastic (S/P) ratio between 2 and 5 and equivalence ratio (ER) from 0 to 0.3. Under the optimum conditions (700 °C, S/P of 3, 12.5 gcat min gHDPE−1 and ER of 0.2), a H2 production of 25.0 wt% was obtained, which is only 28.6 % lower than that obtained in the conventional pyrolysis-steam reforming (P-SR) process. The results obtained confirm the potential of continuous P-OSR process for the selective production of H2.

  • Self-assembled concentric stripes of diamond particles by a pinning-depinning mechanism
    • Paulina Czarnecka-Trela
    • Adam M. Wojciechowski
    • Mariusz Mrózek
    • Maciej Głowacki
    • Robert Bogdanowicz
    • Wojciech Gawlik
    2024 Pełny tekst DIAMOND AND RELATED MATERIALS

    We describe the novel mechanism of spontaneous formation of the concentric stripe patterns of microdiamonds via gradual solvent evaporation from a suspension confined in a teardrop well. The self-organized patterns exhibit a series of arcs with regular spacings varying between hundreds of micrometers and millimeters. They result from an interplay between the directional forced circulation of the solvent and a stick-slip movement of its contact line during the gradual drying of the suspension. We reveal the mechanism of the phenomenon and discuss the effects of various parameters on the obtained structures.

  • Self-organising maps in the analysis of strains of human abdominal wall to identify areas of similar mechanical behaviour.
    • Mateusz Troka
    • Katarzyna Szepietowska
    • Izabela Lubowiecka
    2024 Pełny tekst Journal of the Mechanical Behavior of Biomedical Materials

    The study refers to the application of a type of artificial neural network called the Self-Organising Map (SOM) for the identification of areas of the human abdominal wall that behave in a similar mechanical way. The research is based on data acquired during in vivo tests using the digital image correlation technique (DIC). The mechanical behaviour of the human abdominal wall is analysed during changing intra-abdominal pressure. SOM allow to study simultaneously three variables in four time/load steps. The variables refer to the principal strains and their directions. SOM classifies all the abdominal surface data points into clusters that behave similarly in accordance with the 12 variables. The analysis of the clusters provides a better insight into abdominal wall deformation and its evolution under pressure than when observing a single mechanical variable. The presented results may provide a better understanding of the mechanics of the living human abdominal wall. It might be particularly useful when selecting proper implants as well as for the design of surgical meshes for the treatment of abdominal hernias, which would be mechanically compatible with identified regions of the human anterior abdominal wall, and possibly open the way for patient-specific solutions.

  • Self-Perceived Personal Brand Equity of Knowledge Workers by Gender in Light of Knowledge-Driven Organizational Culture: Evidence From Poland and the United States
    • Wioleta Kucharska
    2024 Pełny tekst SAGE Open

    This study contributes to the limited literature on the personal branding of knowledge workers by revealing that a culture that incorporates knowledge, learning, and collaboration supports (explicit and tacit) knowledge sharing among employees and that sharing matters for knowledge workers’ self-perceived personal brand equity. Analysis of 2,168 cases from the United States and Poland using structural equation modeling (SEM) showed that this knowledge-sharing mechanism differs by country and gender. Findings revealed that in the United States, the knowledge culture and collaboration culture are highly correlated and dominate the learning culture. In both countries, the mistake acceptance component of the learning culture is not supported by knowledge culture as strongly as is the climate component. These findings reveal a bias concerning the acceptance of mistakes as a potential source of learning observed if the culture of knowledge dominates. Moreover, this study uncovers some significant gender differences that might be caused by the gender stereotypes existing in STEM (science, technology, engineering, mathematics). Finally, the study confirms that knowledge workers’ personal branding is a potent motive to smoothen and increase the knowledge-sharing flow in knowledge-driven organizations.

  • Semi-definite programming and quantum information
    • Piotr Mironowicz
    2024 Pełny tekst Journal of Physics A-Mathematical and Theoretical

    This paper presents a comprehensive exploration of semi-definite programming (SDP) techniques within the context of quantum information. It examines the mathematical foundations of convex optimization, duality, and SDP formulations, providing a solid theoretical framework for addressing optimization challenges in quantum systems. By leveraging these tools, researchers and practitioners can characterize classical and quantum correlations, optimize quantum states, and design efficient quantum algorithms and protocols. The paper also discusses implementational aspects, such as solvers for SDP and modeling tools, enabling the effective employment of optimization techniques in quantum information processing. The insights and methodologies presented in this paper have proven instrumental in advancing the field of quantum information, facilitating the development of novel communication protocols, self-testing methods, and a deeper understanding of quantum entanglement.

  • Sensitive method for determination of benzoic acid in beverages and food samples using air–assisted hydrophobic deep eutectic solvent-based dispersive liquid-liquid microextraction
    • Hameed Haq
    2024 Sustainable Chemistry and Pharmacy

    A simple, reliable and rapid air–assisted hydrophobic deep eutectic solvent-based dispersive liquid–liquid microextraction (AA-HDES-DLLME) was developed for analysis of benzoic acid in various beverages and food samples. The final determination stage was performed via UV–visible spectrophotometry. The key parameters (extraction time, HDES type and volume, dispersant volume, pH and sample volume) of the AA-HDES-DLLME method were optimized in detailed using Box–Behnken design. Analysis of variance was used for statistical analysis. Under the optimized conditions, limit of detection (12.1 μg L−1), limit of quantification (40 μg L−1), linearity range (40–1000 μg L−1), and preconcentration factor (140) were determined. While the accuracy of the AA-HDES-DLLME method was investigated with the standard addition approach, its precision was investigated with intraday/interday studies. The method proved to be effective for routine analytical practice for a wide variety of samples. The novelty of the AA-HDES-DLLME method is that it enables the extraction of benzoic acid without the need for heating or centrifugation steps. In this way, the AA-HDES-DLLME method enabled selective extraction of benzoic acid in a shorter time and using less energy compared to similar studies.

  • Sensorless Control of Induction Motor Based on Super-Twisting Sliding Mode Observer With Speed Convergence Improvement
    • Lelisa Wogi
    • Marcin Morawiec
    • Tadele Ayana
    2024 Pełny tekst IEEE Access

    The super twisting sliding-mode observer (ST-SMO) has been proposed to achieve an effective method for alleviating low-order harmonics of measured quantities, issues related to DC drift, and suppression of chattering due to low-frequency sampling. The conventional ST-SMO, on the other hand, suffers from control delay in the convergence trajectory due to the system disturbance, resulting in decreased anti-disturbance capability and impacting the estimation accuracy and energy consumption. This paper proposed an ST-SMO with convergence improvement to address the issue related to the sliding mode controller along the sliding surface. A nonlinear sliding mode manifold is created to achieve the optimal ST-SMO convergence trajectory along the sliding surface. Then, a disturbance compensation term is added to the control law to eliminate the system control delay. In comparison to the conventional ST-SMO, the investigated method can effectively improve the anti-disturbance capability of the induction motor (IM) Observer, resulting in improved speed estimation (rotor flux control under applied load torque disturbances, speed reversal, and zero speed operation), good performance, and stability. The simulation and experimental studies are carried out for an induction motor with a 5.5kW rating. Both simulation and experimental results prove good robustness against the applied load torque disturbances and convergence of rotor speed to its actual value.