Search Results (39)

The method of matched asymptotic expansions is applied to analyze the meniscus around a floating particle. The asymptotic solutions, derived while considering Fraenkel’s warning, are expressed as functions of the filling angle and contact angle. The analytical solutions accurately predict both the filling angle and the position of the three-phase contact line, even for larger $ϵ$ values. The deformed free surface profile around a single floating particle shows excellent agreement with numerical results obtained from transformed equations using the inclination angle of the deformed surface. The matched asymptotic solutions reveal two distinct steady-state interface configurations, with one stable configuration identified through vertical stability analysis. This asymptotic approach enables the construction of stability diagrams for floating conditions, helping determine the maximum floatable particle size or density ratio for sustained flotation. The methodology developed here provides a foundation for future research on buoyancy for particles of various shapes and stability under dynamic conditions. Full article

As the proportion of renewable energy sources integrated into the power grid increases, it imposes significant volatility on the grid, leading to uneven load distribution across certain transmission lines. Rotating Power Flow Controllers (RPFCs) based on Rotating Phase-Shifting Transformers (RPSTs) offer a viable solution to such issues in lines rated at 10 kV and below. This paper begins with a brief introduction to RPFCs, followed by the modeling of their topology for a single-circuit line and the derivation of active and reactive power flow formulas. Notably, this paper introduces intelligent optimization algorithms to this field for the first time, employing an improved hybrid particle swarm optimization (HPSO) algorithm to control the active power while keeping the reactive power constant and subsequently adjusting the reactive power while maintaining the active power steady, thereby achieving power regulation. Using Matlab/Simulink simulations, this strategy was compared with adaptive adjustment strategies, verifying that it exhibits reduced power fluctuations and overshoots during the adjustment process, thus confirming the effectiveness of the adjustment scheme. By leveraging this algorithm in conjunction with simulations, a Q-P operating range diagram for transmission lines was plotted, determining the adjustable range of actual power. Full article

Background/Objectives: This work introduces accuracy- and precision-ROC curves in addition to SS– and PV–ROC curves and shows a novel means of profiling biomarker characteristics for validation of optimal cutoffs in clinical diagnostics and decision making. Methods: This investigation included 91 patients with a confirmed bladder cancer diagnosis and 1152 patients without evidence of cancer. The study performed a quantitative investigation of used-up test cassettes from the visual UBC^® Rapid qualitative point-of-care assay, which had already been applied in routine diagnostics. Using a photometric reader, quantitative data could also be obtained from the test line of the used cassettes. The ROC curves were constructed using different thresholds or cutoff levels to determine the TP/TN and FP/FN values for each threshold at concentrations of 5, 10, 30, 50, 90, 110, 250 and 300 µg/L. The resulting TP/TN and FP/FN values were used to calculate the sensitivity/specificity, accuracy, precision and predictive values in order to plot the ROC curves with integrated cutoff value distributions and their index cutoff diagrams. Results: A common, optimal cutoff value for all the diagnostic parameters was derived with the aid of an ROC index cutoff diagram. It includes higher specificity and an acceptable number of NPVs. As a result, use of a sensitivity–specificity ROC curve and the Youden index only permits the selection of a maximal threshold value or cutoff point for the biomarker of interest but disregards the clinical status of the patient, whereas the precision, accuracy and predictive values give information related to the disease. Conclusions: This work’s novelty compared to the existing methodology includes the first international publication of accuracy- and precision-ROC curves. It enables the investigation of the relationship among the sensitivity, specificity, precision, accuracy and predictive values at varied cutoff levels within a bioassay, presenting these in a single graph consisting of selected receiver operating characteristic (ROC) curves for each parameter, including cutoff distribution curves. This is a transparent method to identify appropriate cutoffs for multiple diagnostic parameters. According to the results, the single-sided use of a sensitivity–specificity ROC curve including the maximal Youden index value as an optimal cutoff or single-point determinations for predictive values cannot provide diagnostic information of the same quality as that given by a multi-parameter diagnostic profile and a multi-parameter cutoff-index-diagram-derived optimal value as presented within this work. The proposed multi-parameter cutoff-index diagram includes novel index cutoff AOX. It is a new different method that allows a quantitative comparison of the results from multi-parameter ROC curves, which cannot be performed with the AUC. However, the methods are different and do not exclude each other. Full article

The existence of propane (C₃H₈) in a CO₂-oil mixture has great potential for increasing CO₂ solubility and decreasing minimum miscibility pressure (MMP). In this study, the enhanced solubility, reduced viscosity, and lowered MMP of CO₂-saturated crude oil in the presence of various amounts of C₃H₈ have been systematically examined at the reservoir conditions. Experimentally, a piston-equipped pressure/volume/temperature (PVT) cell is first validated by accurately reproducing the bubble-point pressures of the pure component of C₃H₈ at temperatures of 30, 40, and 50 °C with both continuous and stepwise depressurization methods. The validated cell is well utilized to measure the saturation pressures of the CO₂-C₃H₈-oil systems by identifying the turning point on a P-V diagram at a given temperature. Accordingly, the gas solubilities of a CO₂, C₃H₈, and CO₂-C₃H₈ mixture in crude oil at pressures up to 1600 psi and a temperature range of 25–50 °C are measured. In addition, the viscosity of gas-saturated crude oil in a single liquid phase is measured using an in-line viscometer, where the pressure is maintained to be higher than its saturation pressure. Theoretically, a modified Peng–Robinson equation of state (PR EOS) is utilized as the primary thermodynamic model in this work. The crude oil is characterized as both a single and multiple pseudo-component(s). An exponential distribution function, together with a logarithm-type lumping method, is applied to characterize the crude oil. Two linear binary interaction parameters (BIP) correlations have been developed for CO₂-oil binaries and C₃H₈-oil binaries to accurately reproduce the measured saturation pressures. Moreover, the MMPs of the CO₂-oil mixture in the presence and absence of C₃H₈ have been determined with the assistance of the tie-line method. It has been found that the developed mathematical model can accurately calculate the saturation pressures of C₃H₈ and/or CO₂-oil systems with an absolute average relative deviation (AARD) of 2.39% for 12 feed experiments. Compared to CO₂, it is demonstrated that C₃H₈ is more soluble in the crude oil at the given pressure and temperature. The viscosity of gas-saturated crude oil can decrease from 9.50 cP to 1.89 cP and the averaged MMP from 1490 psi to 1160 psi at 50 °C with the addition of an average 16.02 mol% C₃H₈ in the CO₂-oil mixture. Full article

Despite their prevalence in almost all publicly orientated conservation settings, sign design receives limited attention in the research literature. We used a remote eye-tracking device to test how visitors read educational signs, maps, and species signage. Three designs, plus a plain-text control sign, were tested for each sign type. Sign content was based on Brackenhurst Botanic Garden, Kenya, and included four different information texts (156–256 words long) and a species information text (64 words long). Four presentations of extinction threat status were also tested as were depictions of trail routes on maps. Data were collected from 51 participants at six cultural venues across Nottingham, U.K. Signs positioned centre-left of an exhibit were read first. Information on the left-hand side of signs was read first and dwelled upon the longest. Signs with a single large image and a single block of text were generally preferred, and images were most frequently recalled. Extinction threat status was most frequently viewed and best recalled from green–red thermometer diagrams and least from the IUCN red list diagram. Map routes were clearest when presented as coloured solid lines. This study indicates the potential benefit of eye-tracking research for measuring sign use and assisting in sign design. Full article

The [ZnL(ONO₂)₂] 1 and [ZnL(NCS)₂] 2 complexes were synthesized using self-assembly of the s-triazine tridentate ligand (L) with Zn(NO₃)₂·6H₂O and Zn(ClO₄)₂·6H₂O/NH₄SCN, respectively. The Zn(II) is further coordinated by two nitrate and two isothiocyanate groups as monodentate ligands in 1 and 2, respectively. Both complexes have distorted square pyramidal coordination environments where the extent of distortion is found to be greater in 2 (τ₅ = 0.41) than in 1 (τ₅ = 0.28). Hirshfeld calculations explored the significant C···O, C···C, N···H, and O···H contacts in the molecular packing of both complexes. The energy framework analysis gave the total interaction energies of −317.8 and −353.5 kJ/mol for a single molecule in a 3.8 Å cluster of 1 and 2, respectively. The total energy diagrams exhibited a strong resemblance to the dispersion energy frameworks in both complexes. NBO charge analysis predicted the charges of the Zn(II) in complexes 1 and 2 to be 1.217 and 1.145 e, respectively. The electronic configuration of Zn1 is predicted to be [core] 4S^0.32 3d^9.98 4p^0.45 4d^0.02 5p^0.01 for 1 and [core] 4S^0.34 3d^9.97 4p^0.53 4d^0.02 for 2. The increased occupancy of the valence orbitals is attributed to the donor→acceptor interactions from the ligand groups to Zn(II). The Zn(II) complexes were examined for their cytotoxic and antimicrobial activities. Both 1 and 2 have good cytotoxic efficiency towards HCT-116 and A-549 cancerous cell lines. We found that 1 is more active (IC₅₀ = 29.53 ± 1.24 and 35.55 ± 1.69 µg/mL) than 2 (IC₅₀ = 41.25 ± 2.91 and 55.05 ± 2.87 µg/mL) against both cell lines. Also, the selectivity indices for the Zn(II) complexes are higher than one, indicating their suitability for use as anticancer agents. In addition, both complexes have broad-spectrum antimicrobial activity (IC₅₀ = 78–625 μg/mL) where the best result is found for 2 against P. vulgaris (IC₅₀ = 78 μg/mL). Its antibacterial activity is found to be good compared to gentamycin (5 μg/mL) as a positive control against this microbe. Full article

Background: This investigation is both a study of potential non-invasive diagnostic approaches for the bladder cancer biomarker UBC^® Rapid test and a study including novel comparative methods for bioassay evaluation and comparison that uses bladder cancer as a useful example. The objective of the paper is not to investigate specific data. It is used only for demonstration, partially to compare ROC methodologies and also to show how both sensitivity/specificity and predictive values can be used in clinical diagnostics and decision making. This study includes ROC curves with integrated cut-off distribution curves for a comparison of sensitivity/specificity (SS) and positive/negative predictive values (PPV/NPV or PV), as well as SS-J index/PV-PSI index–ROC curves and SS-J/PV-PSI index cut-off diagrams (J = Youden, PSI = Predictive Summary Index) for the unified direct comparison of SS-J/PV results achieved via quantitative and/or qualitative bioassays and an identification of optimal separate or unified index cut-off points. Patients and Methods: According to the routine diagnostics, there were 91 patients with confirmed bladder cancer and 1152 patients with no evidence of bladder cancer, leading to a prevalence value of 0.073. This study performed a quantitative investigation of used-up test cassettes from the visual UBC^® Rapid qualitative point-of-care assay, which had already been applied in routine diagnostics. Using a photometric reader, quantitative data could also be obtained from the test line of the used cassettes. Interrelations between SS and PV values were evaluated using cumulative distribution analysis (CAD), SS/PV–ROC curves, SS-J/PV-PSI index–ROC curves, and the SS-J/PV-PSI index cut-off diagram. The maximum unified SS-J/PV-PSI index value and its corresponding cut-off value were determined and calculated with the SS-J/PV-PSI index cut-off diagram. Results: The use of SS/PV–ROC curves with integrated cut-off concentration distribution curves provides improved diagnostic information compared to “traditional” ROC curves. The threshold distributions integrated as curves into SS/PV–ROC curves and SS-J/PV-PSI index–ROC curves run in opposite directions. In contrast to the SS–ROC curves, the PV–ROC and the novel PV-PSI index–ROC curves had neither an area under the curve (AUC) nor a range from 0% to 100%. The cut-off level of the qualitative assay was 7.5 µg/L, with a sensitivity of 65.9% and a specificity of 63.3%, and the PPV was 12.4% and the NPV was 95.9%, at a threshold value of 12.5 µg/L. Based on these set concentrations, the reader-based evaluation revealed a graphically estimated 5% increase in sensitivity and a 13% increase in specificity, as compared to the visual qualitative POC test. In the case of predictive values, there was a gain of 8% for PPV and 10% for NPV. The index values and cut-offs were as follows: visual SS-J index, 0.328 and 35 µg/L; visual PV-PSI index, 0.083 and 5.4 µg/L; maximal reader Youden index, 0.0558 and 250 µg/L; and maximal PV-PSI index, 0.459 and 250 µg/L, respectively. The maximum unified SS-J/PV-PSI index value was 0.32, and the cut-off was 43 µg/L. The reciprocal SS-J index correctly detected one out of three patients, while the reciprocal PV-PSI index gave one out of twelve patients a correct diagnosis. Conclusions: ROC curves including cut-off distribution curves supplement the information lost in “traditionally plotted” ROC curves. The novel sets of ROC and index–ROC curves and the new SS/PV index cut-off diagrams enable the simultaneous comparison of sensitivity/specificity and predictive value profiles of diagnostic tools and the identification of optimal cut-off values at maximal index values, even in a unifying SS/PV approach. Because the curves within an SS-J/PV-PSI index cut-off diagram are distributed over the complete cut-off range of a quantitative assay, this field is open for special clinical considerations, with the need to vary the mentioned clinical diagnostic parameters. Complete or partial areas over the x-axis (AOX) can be calculated for summarized quantitative or qualitative effectivity evaluations with respect to single and/or unified SS-J and PV-PSI indices and with respect to single, several, or several unified assays. The SS-J/PV-PSI index-AOX approach is a new tool providing additional joint clinical information, and the reciprocal SS-J indices can predict the number of patients with a correct diagnosis and the number of persons who need to be examined in order to correctly predict a diagnosis of the disease. These methods could be used in applications like medical or plant epidemiology, machine learning algorithms, and neural networks. Full article

The authors of this article analyze the existing methods and models of technological preparation of machine-building industries. The structure of a three-level simulation model with network-centric control, the structures of individual elements of the simulation model, and the process of simulation modeling are described. The criteria for choosing a rational option for the processing technological route have been determined. During this research, a simulation program was implemented in C++. It allows you to select the optimal scenario for the operation of a production site based on two criteria: time and cost. The volume of implementation is about 2 × 10³ lines of code. A diagram of the modeling algorithm for the implemented program and a description of the classes and their interactions are given in the article. The developed simulation model was tested at a machine-building enterprise using the example of the “Pusher” part, manufactured under single-unit production conditions. The technological equipment used for the manufacture of this part was formed in the form of input data of the simulation model. The results of simulation modeling for the selected part are described. For each variant of the technological processing route, the values of variable costs and the duration of the production cycle were determined. Full article

This paper presents several conclusions based on time domain analysis of the simulation results of several transmission lines that use frequency-dependent dielectrics, highlighting the fiberglass effect on performance. The matching conditions of the circuit are checked based on a Smith chart simulation that represents the magnitude of the reflection coefficient via scattering parameters. A time domain analysis is provided by means of the eye diagram, which allows the study of the rise and fall time, jitter, and eye height and width of the two materials considered to be appropriate for the examination of composite substrates: one conventional substrate, FR4, and one more oriented to high-speed design constraints, N4000-13. Time domain analyses highlight the effect of increasing the rate for our purpose on the composite substrate for coupled or single-ended interconnections or routes on PCBs. Full article

The business world is becoming more competitive. Therefore, it is crucial to increase the flexibility of production by decreasing the time used in the processes of preparing the production lines for new items’ production, reducing changeover and setup times. This paper presents a case study where the main goal is to reduce the setup time of welding robots. Single Minute Exchange of Die (SMED) was implemented, using other tools such as the Spaghetti Diagram, ERCS Analysis (Eliminate, Rearrange, Combine, Simplify), Gemba Walk, Standardized Work, Flowcharts, and Pareto Diagram. The setup time decreased by 36% in the welding robots studied, decreasing the motions by 43% during the changeover process and reducing the time from the categories: “transportation”, “main”, “other”, and “waiting”. In addition to SMED implementation, this study offers an integrated study of several Lean tools and Quality tools to achieve the maximum reduction of changeover and setup times. Full article

In numerous electrical power distribution systems and other engineering contexts, single-line diagrams (SLDs) are frequently used. The importance of digitizing these images is growing. This is primarily because better engineering practices are required in areas such as equipment maintenance, asset management, safety, and others. Processing and analyzing these drawings, however, is a difficult job. With enough annotated training data, deep neural networks perform better in many object detection applications. Based on deep-learning techniques, a dataset can be used to assess the overall quality of a visual system. Unfortunately, there are no such datasets for single-line diagrams available to the general research community. To augment real image datasets, generative adversarial networks (GANs) can be used to create a variety of more realistic training images. The goal of this study was to explain how deep-convolutional-GAN- (DCGAN) and least-squares-GAN- (LSGAN) generated images are evaluated for quality. In order to improve the datasets and confirm the effectiveness of synthetic datasets, our work blended synthetic images with actual images. Additionally, we added synthetic images to the original picture collection to prepare an augmented dataset for symbol detection. In this scenario, we employed You Look Only Once (YOLO) V5, one of the versions of YOLO. The recognition performance was improved, reaching an accuracy of 95% with YOLO V5, after combining the actual images with the synthetic images created by the DCGAN and LSGAN. By incorporating synthetic samples into the dataset, the overall quality of the training data was improved, and the learning process for the model became simpler. Furthermore, the proposed method significantly improved symbol detection in SLDs, according to the findings of the experiments. Full article

Raw materials significantly determine the final composition and properties of a fired ceramic. Raman analysis which characterizes micro- and nanostructures of (coloured) glazes, opacified or not, was applied to shards mostly collected before the 1960s, currently at the Louvre Museum, originated in Anatolia, the Caucasus, Iran and Central Asia, which are, for most of them, characterized by the use of black lines to separate coloured areas, and dated to the period between the 12th and 19th centuries. Measurements were carried out in the laboratory with a blue laser excitation and/or on the conservation site with a mobile device (green laser). Three types of glazes were identified by their nanostructure of the silicate network: (i) a lead-rich glaze analogous to that of Byzantine, Zirid to Hafsid and al-Andalus productions, (ii) a lead-alkali glaze typical of the Ottoman productions of Iznik-Kütahya, and (iii) a mixed (poor lead/lead-free)-alkali glaze typical of Safavid productions. The colour determines the precise composition of the glaze. The identification is not only based on the signature of the stretching mode of the SiO₄ tetrahedron (position of the wavenumber of the component(s)) but also on the position and shape of the continuous luminescence of the Raman background, characteristic of the raw materials used. Lead-tin yellow, Fe-rich, Mn-rich and Cr-rich black pigments and opacifiers made of cassiterite and wollastonite were also identified. The results (type of glaze and deduced processing temperature) were discussed in the light of the ternary phase diagrams visualizing elemental composition determined in previous works and the microstructure examination on the polished section (defining single or multistep firing cycles). Continuity was highlighted on the one hand between the tiles of Bursa, Edirne and Istanbul (Ottoman Iznik-like production) and on the other hand between those of Samarkand area (Timurid) and Iran. The procedure was then applied in the study of three objects (two dishes and a bowl) which are very representative of the productions of the Turkish-Persian cultural areas: a polychrome mina’i cup with decoration representing a rider, an Ottoman Iznik fritware with polychrome floral decoration, and a blue-and-white Safavid ceramic with a decoration representing a shrub. Full article

Complex networks in reality are not just single-layer networks. The connection of nodes in an urban metro network includes two kinds of connections: line and passenger flow. In fact, it is a multilayer network. The line network constructed by the Space L model based on a complex network reflects the geographical proximity of stations, which is an undirected and weightless network. The passenger flow network constructed with smart card big data reflects the passenger flow relationship between stations, which is a directed weighted network. The construction of a line-flow multilayer network can reflect the actual situation of metro traffic passenger flow, and the node clustering coefficient can measure the passenger flow clustering effect of the station on adjacent stations. Combined with the situation of subway lines in Nanjing and card-swiping big data, this research constructs the line network with the Space L model and the passenger flow network with smart card big data, and uses these two networks to construct the multilayer network of line flow. This research improves the calculation method of the clustering coefficient of weighted networks, proposes the concept of node group, distinguishes the inflow and outflow, and successively calculates the clustering coefficient of nodes and the whole network in the multilayer network. The degree of passenger flow activity in the network thermal diagram is used to represent the passenger flow activity of the line-flow network. This method can be used to evaluate the clustering effect of metro stations and identify the business districts in the metro network, so as to improve the level of intelligent transportation management and provide a theoretical basis for transportation construction and business planning. Full article

The investigation of the structural, luminescent and photoconversion properties (color coordinates, correlated color temperature, color rendering index and luminous efficacy) of the single-crystalline films of Ce³⁺-doped Tb_1.5Gd_1.5Al₅O₁₂:Ce mixed garnet with variable film thickness was performed in this work. These film converters were grown on undoped Y₃Al₅O₁₂ substrates using the liquid phase epitaxy technique. When combined directly with blue LEDs that were commercially available in the market, the developed garnet film converters were responsible for producing white light. The trend line on the color coordinate diagram was obtained for the first time for the Tb_1.5Gd_1.5Al₅O₁₂:Ce converters with the systematic variation in film thickness in the range of 45–82 µm. Under 464 nm blue LED excitation, the investigated converters with a thickness of 55 µm resulted in an ideal white color. Full article

This article describes a new quantitative evaluation method for the degree of dissociation of a compound depending on the curvature of the liquidus line curve. The main point of this method was to determine the specific expressions for dissociation parameters according to the mathematical model of the crystallization line of the compound on the phase diagram. This was based on generally accepted thermodynamic relations. Empirically, it has now been established that for many types of phase equilibria, a common feature is the presence of a correlation dependence between the ratios of the real Gibbs energy of the distribution of components to its ideal component. The osmotic coefficient of Bjerrum–Guggenheim was used as a measure of the deviation of the system from ideality. This coefficient can be in an analytical form depending on the temperature and composition of the phases. The obtained correlation dependence of the osmotic coefficient of Bjerrum–Guggenheim on the ratio of the activity of the liquid and solid phase has been used to develop a mathematical apparatus to analytically describe the lines and surfaces of the crystallization phases. Accordingly, a single analytical basis, as a universal dependence of the modified Schröder–Le Chatelier equation, has been applied. Based on this equation, the conditions have been defined to develop an equilibrium method with which to calculate the thermal dissociation of chemical compounds. The principle of this method has been examined based on the two-component iron-titanium system. The numerical results of the degree of dissociation of the congruent Fe₂Ti compound have been obtained using the Gibbs energy of the dissociation reaction and the reaction constant. However, it has been found that the degree of dissociation in the compound Fe₂Ti was 0.04%. Demonstrative material for the behavior of the osmotic coefficient of Bjerrum–Guggenheim under boundary conditions has been presented as an assessment criterion of melt structures. The diagrams of the Φi function of the crystallizing phases near the melting temperature of congruently melting compounds (Tm.) have been mathematically studied. Thus, this study demonstrates that Φ${}_{A_m{B}_n}^{\prime }$ diagrams tended to zero and approached the melting temperature of the compound ${\mathrm{T}}_{m,A_m{B}_n}^{}$, i.e., above the melting temperature of this compound Φ${}_{A_m{B}_n}^{\prime }$→∞; then,$\ln x_{A_m{B}_n}$→0, and, as a result, $x_{A_m{B}_n}$→1. Full article