Actual Properties Research Articles

Simplified Life Cycle Cost Estimation of Low-Rise Steel Buildings Using Fundamental Period

In the current study, a simplified seismic life cycle cost (LCC) estimation procedure is proposed utilizing the mean values of the structure’s main input variables. The main input variables of the building are used for constructing a relationship between the structural fundamental period (T) and an average estimation of the LCC (LCCavg). Using the actual building properties related to damage probability, the T–LCCavg relationship is used to obtain the final LCC (LCCfin). The equivalent single degree of freedom (ESDOF) model and SAC-FEMA framework are utilized for damage probability calculation. The dispersion measure in demand is approximately calculated based on the mean plus one standard deviation of the seismic hazard response spectrum, and, then, verified through nonlinear time history (NLTH) analyses of the original structure. Five and three-story steel buildings are used as case studies for verification of the proposed method. The analysis results indicate that the proposed procedure provides reasonable LCC estimations for low-rise buildings dominated by the fundamental mode of vibration.

Benign and Malignant Skin Lesions: Dielectric Characterization, Modelling and Analysis in Frequency Band 1 to 14 GHz.

This paper aims to characterize Non-Melanoma malignancies and their corresponding benign conditions in ex-vivo/in-vivo tissue environments to study the feasibility of microwave techniques for skin cancer detection. The dielectric dataset is developed across the frequency band 1 to 14 GHz using Keysight slim-form and RG405 probe characterization systems. The acquired reflection data captured by the systems is converted to dielectric values using the Open-Water-Short and Open-Water-Liquid calibration methods, respectively. Furthermore, the impact of anaesthesia application during skin excision procedure on ex-vivo dielectric data is investigated. The observations suggest that the dielectric properties (DPs) of excised skin lesions may not accurately represent actual tissue properties as they vary significantly (Dielectric Constant Contrast = 30.7%, Loss-Factor Contrast = 66.6%) compared to pre-excision conditions. In-vivo dielectric data analysis indicates that when compared to healthy skin, malignant Basal Cell Carcinoma presents increased DPs (dielectric constant & loss factor) of (24.8 & 38.6 %), respectively. On the other hand, for malignant Squamous Cell Carcinoma and pre-malignant Actinic Keratosis, the measured results show decreased DPs (dielectric constant & loss factor) accordingly by (19.4 & 18.2 %) and (19.2 & 27.9 %). The corresponding benign lesions have less than 13 % dielectric contrast compared to healthy skin across the tested band. The significant contrasts between in-vivo healthy and cancerous skin DPs strongly suggest the viability of the microwave band for skin cancer detection. The research finding of this study would be critical in developing a portable electromagnetic system for skin cancer detection.

Power Grid Structure Performance Evaluation Based on Complex Network Cascade Failure Analysis

A safe and stable operation power system is very important for the maintenance of national industrial security and social economy. However, with the increasing complexity of the power grid topology and its operation, new challenges in estimating and evaluating the grid structure performance have received significant attention. Complex network theory transfers the power grid to a network with nodes and links, which helps evaluate the system conveniently with a global view. In this paper, we employ the complex network method to address the cascade failure process and grid structure performance assessment simultaneously. Firstly, a grid cascade failure model based on network topology and power system characteristics is constructed. Then, a set of performance evaluation indicators, including invulnerability, reliability, and vulnerability, is proposed based on the actual functional properties of the grid by renewing the power-weighted degree, medium, and clustering coefficients according to the network cascade failure. Finally, a comprehensive network performance evaluation index, which combines the invulnerability, reliability, and vulnerability indicators with an entropy-based objective weighting method, is put forward in this study. In order to confirm the approach’s efficacy, an IEEE-30 bus system is employed for a case study. Numerical results show that the weighted integrated index with a functional network could better evaluate the power grid performance than the unweighted index with a topology network, which demonstrates and validates the effectiveness of the method proposed in this paper.

Extending the NNO Ballistic Limit Equation to Foam-Filled Dual-Wall Systems

A key component in the quantitative assessment of the risk posed to spacecraft by the micrometeoroid and orbital debris (MMOD) environment is frequently referred to as a ballistic limit equation (BLE). A frequently used BLE for dual-wall configurations (which are commonly used on spacecraft to protect them against the MMOD environment) is the New Non-Optimum, or “NNO”, BLE. In design applications where a BLE is needed for a new structural system that has not yet been tested, but resembles to a fair degree a dual-wall system, it is common practice to equivalence the materials, thicknesses, etc., of the new system to the materials, thicknesses, etc., of a dual-wall system. In this manner, the NNO BLE can be used to estimate the failure / non-failure response characteristics for the new system. One such structural wall system for which a BLE does not yet exist is a dual-wall system that is stuffed with a lightweight polymer-based foam material. In this paper we demonstrate that the NNO BLE, in its original form, frequently over- or under-predicts the response of such a system. However, when the NNO BLE is modified to more properly include the effects of the presence of the foam as well as the actual material properties of the walls and the impacting projectile, there is a marked improvement in its predictive abilities.

MODEL DEVELOPMENT AND PERFORMANCE IMPROVEMENT OF A PHOTOVOLTAIC-THERMOELECTRIC SYSTEM BY INTEGRATING AND OPTIMIZING PHASE CHANGE MATERIALS

Integrating phase change materials (PCMs) with concentrated photovoltaic-thermoelectric (PV-TE) systems can effectively control the interface temperature between PV and TE components and improve the full solar-spectrum utilization efficiency. However, since the structure of photovoltaic-phase change material-thermoelectric (PV-PCM-TE) systems is complex and the temperatures among the components are coupled and affect each other, the photo-thermal-electric conversion characteristics under the actual physical properties need to be analyzed by a more detailed model, and the suitable operating conditions for PV-PCM-TE systems remain clear. There is still a lack of the method for improving the system performance. Therefore, a three-dimensional transient model is established herein by combining the Monte Carlo ray-tracing method and finite volume method to simulate the complex energy conversion processes of the PV-PCM-TE system. Based on this, performances of PV-PCM-TE, PV-TE, and PV systems are compared under different operating conditions, and the applicable conditions for PV-PCM-TE systems are analyzed. Then effects of key parameters of the phase change module are investigated. In the end, to further improve the system performance, a partition screening method of PCM is proposed considering the nonuniform solar radiation on photovoltaic surfaces, and the selection and layout area of PCMs are optimized. The results present that the applicable operating conditions are low concentration ratio (< 20) and low heat transfer coefficient (< 20 W·m<sup>-2</sup>·K<sup>-1</sup>). In terms of structural parameters, the system power generation is most significantly affected by the width. In terms of PCM physical properties, it is most affected by the PCM density, followed by latent heat. For different concentration ratios, there are different optimal melting points to achieve the highest power generation. The proposed PCM partition screening method can efficaciously control PV-TE interface temperature, and reduce photovoltaic cells' temperature by 47°C. The system efficiency can be increased by 4.8% and 4.2% after the optimization compared with that of the single PV cell and the traditional PV-TE system, respectively.

Dispositionalism’s (grand)daddy issues: time travelling and perfect masks

AbstractThere is a tension between Dispositionalism––the view that all metaphysical modality is grounded in actual irreducible dispositional properties––and the possibility of time travel. This is due to the fact that Dispositionalism makes it much harder to solve a potentiality-based version of the grandfather paradox. We first present a potentiality-based version of the grandfather paradox, stating that the following theses are inconsistent: 1) time travel is possible, 2) powers fully ground modality, 3) self-defeating actions are impossible, 4) time-travellers retain their intrinsic powers upon time-travelling, and 5) time-travellers are ordinary agents with basic intrinsic potentialities. We then consider a number of potential solutions, and find them wanting. We argue that the metaphysical impossibility of performing a self-defeating action acts as a necessary perfect mask––while time-travel lets us “slip” the potentiality under the mask, thus generating the contradiction. We conclude considering what are the options for the dispositionalist.

Физико-химические свойства наночастиц золота в рудах и катализаторах

Introduction. At present, in the instrumental study of the mineral forms of finding gold in geogenic and technogenic ores, more and more attention has been paid to free gold, with a size of several nanometers. Such gold has been found in almost all types of its geogenic ores: starting with deposits of primary sulfide ores and ending with various gold-bearing placers. A similar situation is observed with technogenic gold-bearing ores accumulated in numerous dumps and tailings. At the same time, with the increase in research on nanogold, not only its fundamental, but also practical importance grows, because. in theoretical and applied research, more and more of its actual physical and chemical properties and previously unknown phenomena and effects accompanying them are discovered and clarified. Research methods and materials. An important aspect is the instrumental study of the geometry of various forms of nanogold occurrence in natural (geogenic) and technogenic ores and minerals. The instrumental and analytical part of our research was based on the visualization of nanoparticles obtained from the Nanjing Research Institute of the Chemical Industry under Sinopec (PRC), carried out on a JEOL 2010F microscope. Research results. The studied gold nanoparticles were presented in the form: • spherical fullerene-like monoparticles; • fullerene-like gold cells, consisting of a different number (from 13 to 20 clusters) of gold nanoparticles; • self-organized «fractal» dendrites; • rather complex composites with the participation of nanogold; • various aggregates of nanoparticles, etc. The concentrations of gold nanoparticles vary significantly from one deposit to another and between individual ore facies (even within the same deposit). Discussion of the obtained results. It was found that nanogold can be contained in arsenopyrites in 2 main forms: a) as a structurally bound solid solution (Au + 1) located in the lattice of this mineral; b) in separate mineral inclusions of submicron size or nanoparticles. Gold nanoparticles (5-10 nm in size) detected in arsenopyrite in concentrations up to 4% mass fraction are sufficiently representative to account for their amount in gold-bearing ores. A gold nanoparticle with a size of 3 nm usually has an average coordination number CN = 9.5, similar nanoparticles with a size of 1 nm have an average CN = 6, and nanoparticles with a size of 0.5–1 nm have an average CN = 3.6. Conclusion. To date, a nanoparticle catalyst has been developed in which gold clusters are attached to metal oxides that are semiconductors. At the same time, their number is very limited and includes only Fe2O3, TiO2, CeO2, and MgO compounds, which can be used not only in the form of nanoparticles, but also nanofilms. Such an innovative nanocatalyst ensures the efficient flow of a number of oxidative and other processes with hydrocarbons at normal temperatures, which is difficult to achieve by other methods. Findings. The article presents the results of studies of the physicochemical properties of gold nanoparticles installed in ores and catalysts. The morphology of gold nanoparticles has been established. The character of gold speciation in various sulfides is determined. The presence of gold nanoparticles in ores and rocks in the state of colloids has been confirmed. The catalytic activity of nanoparticles of various shapes and chemical states was revealed, depending on the values of the ambient temperature. The results of the research can be useful in the enrichment of gold-bearing ores of upland deposits.

Development of Laboratory-made Compositions of Concrete Based on the Certain Raw Materials and Restrictions of the AKKUYU NPP Construction

Introduction. Concrete is one of the materials most frequently used in construction thus the technologies of its manufacturing are being constantly improved. In our article we will develop the laboratory-made compositions of concrete based on the certain raw materials resources and restrictions existing at the construction site of one of the nuclear power plants in the Republic of Türkiye. One of the results of elaborating the concrete composition design technology is the selfcompacting concrete that fosters sustainable construction due to significant reduction of energy consumption. Self–compacting concrete is a type of concrete that can completely fill in the formwork only by gravity, without need for concrete consolidating by vibration. Its high fluidity and filling capacity are its advantages over conventional concrete. Self-compacting concrete has high fluidity, high water retention capacity, good strength. The aim of the study was to obtain the laboratory-made compositions of concrete based on the certain raw materials resources and restrictions existing at the construction site.Materials and methods. The list of raw materials potentially meeting the design documentation requirements has been specified. The concrete compositions using various aggregates were selected, the minimum amount of cement was determined, aimed among other things at corrosion resistance improvement.Results. Based on the restrictions existing at the construction site and according to the results of raw materials analysis including their oxide composition specification, 5 compositions were developed for each of NPP engineering structures.Discussion and conclusions. The study has completed all the tasks set forth, the main of which are: analysis of the raw materials market, laboratory studies of raw materials, specification of their actual physical and mechanical properties, identification of components meeting the standards and requirements, obtaining the laboratory-made compositions of concrete mixtures classified by their designation. The perspectives for further research are indicated.

The Optimization of a Numerical Steel Foundry Simulation Through a Characterization of the Thermal Properties of the Materials

In many foundries, numerical simulation is used to determine the origins of different defects as this tool allows the acceleration of the design process. However, the databases provided by different software do not seem to tally with the actual properties of the material. In fact, every foundry uses a different grade of steel and varying mixtures of sand. An evaluation of the impact of different material properties showed the importance of measuring every physical property to improve the database of the software. Following this, an experiment was conducted to evaluate the gap between numerical simulations and the results obtained through experimentation. This experiment, called thermal analysis, consists in measuring the solidification and cooling of a cylinder filled with liquid steel. After the calculation of the steel properties and a simulation with real experimental parameters, a comparison between each cooling curve was realized. This comparison shows that the calculated properties provide a simulated cooling curve which is closer to the experimental curve than the properties in the original database. We did not explore all of the metal properties in this study, but the modification of the sand properties was explored, together with the thermal conductivity of the steel and sand. These other measurements will be obtained in a future study.

Novel Method for Characterizing the Mechanical Properties of the Cement Sheath Based on Hollow-Cylinder Specimen and Multiaxial Load Tests

Summary Mechanical properties such as Young's modulus, Poisson's ratio, and strength are important parameters for evaluating the cement sheath integrity. However, the current triaxial testing methods for the mechanical properties of intact-cylinder cement specimens ignore the “ring” shape of the wellbore cement sheath and its nonuniform 3D stress distribution, which may lead to deviations from the actual mechanical properties of the wellbore cement sheath that can affect the theoretical analysis results. In this study, we designed a hollow-cylinder cement specimen to address the aforementioned conditions and conducted uni, tri, and multiaxial compression tests to analyze the differences in the deformation, damage, and mechanical failure of the hollow- and intact-cylinder cement specimens. It was found that under the same confining pressure, the Young’s modulus of the hollow-cylinder cement specimen with hole pressure was approximately 1.2 times that of the intact-cylinder cement specimen; however, the difference in Poisson’s ratio was not significant. The uniformity of the radial and circumferential stress distributions in the hollow-cylinder cement specimens was the main factor affecting the volumetric strain curves and the damage threshold. Under tri and multiaxial compression conditions, the deviatoric stress of the hollow-cylinder cement specimens was higher than that of the intact-cylinder cement specimens. Compared with the Mohr-Coulomb criterion, the twin-shear unified strength theory can more accurately reflect the relationships between the radial, circumferential, and axial stresses and the strength of the hollow-cylinder cement specimens. Through a failure test of the cement sheath based on a self-developed wellbore simulation device, it was verified that the mechanical properties of the hollow-cylinder cement specimens can better reflect the failure law of the wellbore cement sheath compared with intact-cylinder cement specimens. The findings of this study can contribute to the understanding of the mechanical behavior of wellbore cement sheaths.

Research into Impact of Leaving Waste Rocks in the Mined-Out Space on the Geomechanical State of the Rock Mass Surrounding the Longwall Face

Backfilling technology is not always used by mining enterprises, which is conditioned by technological and economic factors, such as the need for high mining rates and costs for the technological processes of transporting backfill materials from the daylight surface to the mined-out space. This concerns the underground mining of hard coal, which is a strategic energy resource, in the mines of Ukraine. This paper aims to study the effect of leaving the waste bottom rocks in the mined-out space of the longwall face without their drawing to the earth’s surface on the geomechanical state of the rocks surrounding the longwall face. The geomechanical assessment of the stress state of the rock mass surrounding the longwall face, when leaving the waste rocks from the seam bottom rocks in the mined-out space, is performed by the finite element method using the Ansys software package. A geomechanical model has been developed and substantiated, which adequately reflects the mining-geological conditions for seam mining within the extraction site, the actual structure and properties of the coal-bearing rock stratum, the parameters of the longwall face and the modified powered support for the processes of leaving the rocks in the mined-out space. The values and patterns have been determined of the decrease in the stress intensity concentrations in the coal-bearing roof mass in the frontal bearing pressure zone and destressing zone with an increase in the ratio of the rock pack thickness to the extracting seam thickness. The relative indicators of the load on the powered support section and the lowering of its roof have been determined by the ratio of the thickness of the rock pack formed in the mined-out space to the extracting seam thickness. The proposed mining method is of significant commercial and research interest for owners of coal mines developing thin coal seams because environmental costs for placing waste on the surface are reduced, and the energy potential of coal is increased due to the separation of waste rocks from coal in underground conditions. The need for a cycle of beneficiation of mined mass is eliminated and the geomechanical conditions of coal mining processes are improved.

Different ways for HAZ microstructure preparation and testing on high alloy steel

The heat-affected zone (HAZ) is the part of the weld that is affected by the heat generated by the welding process during welding. The microstructure of the HAZ is very heterogeneous and consists of different zones such as the coarse-grained HAZ, the fine-grained HAZ, the intercritical HAZ, and the over-tempred HAZ [1]. All these zones are very narrow and their properties are slightly different. These properties affect the integrity of the entire weld, so in many cases the HAZ may be the worst part of the weld. Another challenge is determining the properties of the individual HAZ regions, since the entire HAZ is very narrow and inhomogeneous. For this reason, many properties cannot be determined accurately, with the exception of a few, such as hardness, for which only a small region is sufficient for measurement. Therefore, it is important to know how to produce the individual microstructure of a HAZ in a wider range of the material in order to determine the actual properties of such a HAZ. One of the ways is to measure the welding parameters during welding to determine the actual influence of the thermal cycle on the formation of the invidual microstructure of HAZ in the weld. Moreover, it is crucial to repeat this weld thermal cycle in an unaffected base metal on a thermal welding simulator to obtain a suitable microstructure of the HAZ [1,2]. The second option is to prepare the microstructure in the furnace by slow heating which is followed by rapid cooling [1,3]. Both processes must be precise and accurate to obtain suitable HAZ microstructures. This article addresses the challenges of producing HAZ microstructures on the high-alloy steel CT781, which is widely used in the automotive industry for parts subjected to high dynamic loads.

CONSUMER BEHAVIOR IN TOURISM: FEATURES OF THE MODEL AND METHODS OF STUDY

The article examines the features of the model and methods of studying consumer behavior in tourism. The relevance of the chosen topic of the article is determined by the dynamics of changes in the consumer behavior of tourists, radical changes in their preferences and decision-making criteria under various external influences, primarily the COVID-19 pandemic and military operations. It is noted that the behavior of consumers of services in the market of the hospitality and tourism industry has its own characteristics related to the immateriality of tourist services, the delayed period and remoteness of the place of consumption, inflated expectations of tourists, reflection and evaluation of the tourist's own experience.
 A five-level model of consumer-tourist behavior has been adapted for the field of tourism and it is concluded that the greater is the gap between the expected and actual properties of the tourist product, the more acute is the consumer's dissatisfaction, which may affect the consumer's further behavior, his/her tourist motives, and re-appeal.
 The methods of research of consumer behavior in tourism are considered, the attention is focused on the survey method and focus groups, which are actively used in tourism practice. The results of the latest research on consumer behavior according to the own methods of global consulting agencies, travel aggregators, expert communities, professional organizations, travel portals, which should be taken into account by the players of the travel market, are described.
 In general, the understanding of the stages, a tourist goes through in the process of buying a tour, gives the travel company the opportunity to fully satisfy his/her needs, establish long-term interaction and increase loyalty. And the understanding of the role of various participants in the process of purchasing and the factors that influence purchasing behavior when buying a tourist product enables the travel company to develop an effective program to support the demand for tourist services.
 It is concluded that in order to increase the level of satisfaction of tourists, it is necessary to address the following factors: safety, emotions, hospitality of residents, ecology, tourist infrastructure, quality of service, logistics, availability and completeness of tourist information, convenience of planning and booking a trip, prices. It is also important to pay attention to the motives of tourists for traveling and to take into account the emergence of a new solvent young generation of consumers who have their own consumer preferences.

Back Analysis of Geotechnical Engineering Based on Data-Driven Model and Grey Wolf Optimization

Geomaterial mechanical parameters are critical to implementing construction design and evaluating stability through feedback analysis in geotechnical engineering. The back analysis is widely utilized to identify and calibrate the geomaterial mechanical properties in geotechnical engineering. This study developed a novel back-analysis framework by combining a reduced-order model (ROM), grey wolf optimization (GWO), and numerical technology. The ROM was adopted to evaluate the response of the geotechnical structure based on a numerical model. GWO was used to search and identify the geomaterials properties based on the ROM. The developed back analysis framework was applied to a circular tunnel and a practical tunnel for determining the mechanical property of the surrounding rock mass. The results showed that the ROM could be an excellent surrogated model and replaced it with the numerical model. The obtained geomaterial properties were in excellent agreement with the actual properties. The deformation behavior captured by the developed framework was consistent with the theoretical solution in a circular rock tunnel. The developed framework provides a practical, accurate, and convenient approach for calibrating the geomaterial properties based on field monitoring data in practical geotechnical engineering applications.

Measurement of the Balance Stability Angle to Predict the Stability Ratio in Patients With Recurrent Anterior Shoulder Dislocation: A Novel Computed Tomography-Based Protocol.

The stability ratio (SR) is an important biomechanical parameter for evaluating glenoid stability in patients with recurrent anterior shoulder dislocation (RASD), and it cannot be practically and conveniently measured in clinical scenarios. To investigate a novel computed tomography (CT)-based protocol to estimate the SR efficiently. Descriptive laboratory study. A total of 102 patients with RASD were included. Demographic information, CT scans, and bone defect area (BDA) were collected. The new protocol, based on balance stability angle (BSA) measurements on CT, was conducted to estimate the SR (SRCT) by 2 surgeons independently. Biomechanical testing was then performed on patient-specific 3-dimensional (3D)-printed glenoid models to calculate the SR (SR3Dprint), which was used to (1) analyze the reliability of SRCT and (2) examine if the BDA could predict SR3Dprint. To validate whether the 3D-printed glenoid could reflect the actual biomechanical properties of the shoulder, the SR from 5 cadaveric glenoid specimens (SRcadaver) was also calculated and compared with that from the 3D-printed glenoid (SR3Dprint) under 6 osteotomy conditions. Linear regression and intraclass correlation coefficients (ICCs) were used for statistical analysis. The interrater reliability of SRCT measurements was high (ICC = 0.95). SRCT was highly correlated with SR3Dprint (R 2 = 0.86; ICC = 0.92). The mean BDA was 11.44% ± 6.72% by the linear ratio method, with a weak correlation with SR3Dprint (R 2 = 0.31; ICC = -0.46). The cadaveric validation experiment indicated that SRcadaver was highly correlated with SR3Dprint (R 2 = 0.86; ICC = 0.77). Results indicated that (1) the proposed CT-based protocol of obtaining BSA measurements is promising for the SR estimation in patients with RASD, (2) the BDA was not an effective parameter to predict the biomechanical SR, and (3) the 3D-printed glenoid could reflect the biomechanical properties of cadaveric shoulders regarding the SR estimation. Traditional BDA measurements cannot accurately reflect the biomechanical stability of the glenoid. The newly proposed CT-based protocol is practical for surgeons to estimate the SR.

Influence of the prestressed layer on spherical transducer in sound radiation performance

To improve the acoustic radiation performance of the spherical transducer, a prestressed layer is formed in the transducer through fiber winding. The influence of the prestressed layer on the transducer is studied from the effects of the radial prestress ([Formula: see text][Formula: see text]) and acoustic impedance, respectively. First, a theoretical estimation of [Formula: see text][Formula: see text] is established with a thin shell approximation of the prestressed layer. Then, the acoustic impedance is measured to evaluate the efficiency of sound energy transmission within the prestressed layer. Further, the ideal effects of [Formula: see text][Formula: see text] on the sound radiation performances of the transducer are analyzed through finite element analysis (FEA). Finally, four spherical transducers are fabricated and tested to investigate their dependence of actual properties on the prestressed layer. The results show that with the growth of [Formula: see text][Formula: see text], the acoustic impedance of the prestressed layer grows, mitigating the enormous impedance mismatch between the piezoelectric ceramic and water, while increasing attenuation of the acoustic energy, resulting in a peak value of the maximum transmitting voltage response ([Formula: see text]) at 1.18 MPa. The maximum drive voltage increases with [Formula: see text][Formula: see text], leading to a steady growth of the maximum transmitting sound level ([Formula: see text]), with a noticeable ascend of 3.9 dB at a 3.44 MPa [Formula: see text][Formula: see text]. This is a strong credibility that the prestressed layer could improve the sound radiation performance of the spherical transducer.

Ring stage classification of Babesia microti and Plasmodium falciparum using optical diffraction 3D tomographic technique

BackgroundBabesia is an intraerythrocytic parasite often misdiagnosed as a malaria parasite, leading to inappropriate treatment of the disease especially in co-endemic areas. In recent years, optical diffraction tomography (ODT) has shown great potential in the field of pathogen detection by quantification of three-dimensional (3D) imaging tomograms. The 3D imaging of biological cells is crucial to investigate and provide valuable information about the mechanisms behind the pathophysiology of cells and tissues.MethodsThe early ring stage of P. falciparum were obtained from stored stock of infected RBCs and of B. microti were obtained from infected patients during diagnosis. The ODT technique was applied to analyze and characterize detailed differences between P. falciparum and B. microti ring stage at the single cell level. Based on 3D quantitative information, accurate measurement was performed of morphological, biochemical, and biophysical parameters.ResultsAccurate measurements of morphological parameters indicated that the host cell surface area at the ring stage in B. microti was significantly smaller (140.2 ± 17.1 µm2) than that in P. falciparum (159.0 ± 15.2 µm2), and sphericities showed higher levels in B. microti-parasitized cells (0.66 ± 0.05) than in P. falciparum (0.60 ± 0.04). Based on biochemical parameters, host cell hemoglobin level was significantly higher and membrane fluctuations were respectively more active in P. falciparum-infected cells (30.25 ± 2.96 pg; 141.3 ± 24.68 nm) than in B. microti (27.28 ± 3.52 pg; 110.1 ± 38.83 nm). The result indicates that P. falciparum more actively altered host RBCs than B. microti.ConclusionAlthough P. falciparum and B. microti often show confusable characteristics under the microscope, and the actual three-dimensional properties are different. These differences could be used in differential clinical diagnosis of erythrocytes infected with B. microti and P. falciparum.Graphical

Intermediate determinism in general probabilistic theories

Quantum theory is indeterministic, but not completely so. When a system is in a pure state there are properties it possesses with certainty, known as actual properties. The actual properties of a quantum system (in a pure state) fully determine the probability of finding the system to have any other property. We will call this principle, wherein the deterministic elements of a theory completely characterise the probabilistic elements, intermediate determinism. In dimensions of at least three, intermediate determinism in quantum theory is guaranteed by the structure of its lattice of properties. This observation follows from Gleason’s theorem, which is why it fails to hold in dimension two. In this work we extend the idea of intermediate determinism from properties to measurements. Under this extension intermediate determinism follows from the structure of quantum effects for separable Hilbert spaces of any dimension, including dimension two. Then, we find necessary and sufficient conditions for a general probabilistic theory to obey intermediate determinism. We show that, although related, both the no-restriction hypothesis and a Gleason-type theorem are neither necessary nor sufficient for intermediate determinism.

Analytical-based simulation approach for an anion exchange membrane fuel cell

An analytical and empirical-based 1-D, non-isothermal, steady-state model for anion exchange membrane fuel cell capable of capturing two-phase phenomena is presented in this study. Coupled multi-physics including mass and charge transport, electrochemical reactions, heat transfer, and two-phase water transport are considered in the model and the simulated results are compared to experimental data. To better represent actual material properties and localized conditions, the model applies multilayer discretization in the gas diffusion electrode to enhance prediction accuracy. The model successfully predicts the baseline performance at 70 °C, 131 kPa abs., 92% RH with pure H2/O2 gas as well as the limiting current at 10% H2. The robust simulation approach allows for simplistic and accurate estimation of cell performance without the complications of applying two-phase parameters and expensive computational need for numerical models. In addition, the results from the sensitivity studies of material properties and operating conditions provide valuable insights on water management strategies and optimal component design for advancing anion exchange membrane fuel cell technology.

Study Investigates Foam Use for Control of Pipeline Slugging

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22235, “Foams To Control Slugging Issues in Pipelines—From Laboratory to Simulation,” by Ivy C.C. Hsia, Bishop Falope, and Nor Hadhirah Halim, Petronas, et al. The paper has not been peer reviewed. Copyright 2022 International Petroleum Technology Conference. Reproduced by permission. _ In one of the operator’s Malaysian fields, hydrodynamic slugging, or two-phase liquid/gas flow instability in the pipeline, has caused losses in flow capacity and intense vibration at the separator, leading to integrity issues. To understand how the behavior of foams in a pipeline affect or alleviate slugging performances, foam behavior was simulated using the OLGA (short for “oil and gas”) simulator, a commercial dynamic multiphase-flow-simulation software. This study showed that foams were able to slow gas velocity and diminish liquid fluctuations, thus reducing slugging in a problematic pipeline. Challenges Posed by Slugging Hydrodynamic slugging or instability of waves at certain liquid/gas flow rates in the pipeline were concerns in several fields in Malaysia. In one such field, almost 50% of the loss in flow capacity (i.e., liquid holdup) from a producing pipeline was the result of slugging, causing gas-production deferments of as much as 30 million scf/D. Severe vibrations from the pipeline to the separator often were felt at the platform, leading to questions about the mechanical integrity of the separator and anticipated high maintenance costs. The issues of slugging can be solved with the use of foams introduced into the pipeline to slow down gas velocity and enhance mixture with liquid. Foam injection into the wellbore has proved to act as a flow stabilizer, thus removing the slugging in the well and improving gas lift. Foams from surfactant injection increase the viscosity of gas, thus reducing gas movement and velocity but with a pressure penalty. Surfactant concentration also decreases the liquid’s surface tension to a minimum value reached when micelles start to form, called the critical micelle concentration (CMC). A thorough understanding of reduction of liquid surface tension is critical. The inclusion of crude oil into the authors’ laboratory tests is intended to establish the actual performance of the surfactant and the effect of crude oil on viscosity and interfacial tension (IFT) to replicate actual fluid properties (i.e., water cut and emulsion tendencies of the field). The software used simulates flow under actual pipeline conditions. A base model was built to establish slugging conditions using parameters obtained from the field. The model was modified to include input parameters of foams such as viscosity and IFT between two phases to determine if they can suppress foams; this was achieved by reading changes in the total liquid volume flow coming from the pipeline throughout the extent of the pipeline. In the complete paper, the authors sought to understand how to determine foam viscosity and interfacial tension in the presence of crude oil using precision laboratory instrumentation and then used these measurements as inputs into the simulation software to calculate the percent reduction in liquid flow volume and fluctuations of an actual pipeline facing slugging issues.